U.S. patent number 11,264,192 [Application Number 17/040,398] was granted by the patent office on 2022-03-01 for circuit interrupter.
This patent grant is currently assigned to PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.. The grantee listed for this patent is Panasonic Intellectual Property Management Co., Ltd.. Invention is credited to Yoshihisa Fukuda, Kenji Kanematsu, Shinya Kimoto, Kazuhisa Kinoshita, Masato Nakamura.
United States Patent |
11,264,192 |
Fukuda , et al. |
March 1, 2022 |
Circuit interrupter
Abstract
A circuit interrupter includes a fixed terminal, a movable
contactor, a moving mechanism, a squib, and accommodation. The
fixed terminal includes a fixed contact. The movable contactor
includes a movable contact connected to the fixed contact. The
moving mechanism is configured to move the movable contactor from a
closed position where the movable contact is connected to the fixed
contact to an open position where the movable contact is separated
from the fixed contact. The squib is configured to generate gas by
combustion. The accommodation is for accommodating the fixed
contact and the movable contactor. In the circuit interrupter, the
gas is introduced into the accommodation.
Inventors: |
Fukuda; Yoshihisa (Osaka,
JP), Kimoto; Shinya (Osaka, JP), Kanematsu;
Kenji (Osaka, JP), Kinoshita; Kazuhisa (Osaka,
JP), Nakamura; Masato (Hyogo, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Panasonic Intellectual Property Management Co., Ltd. |
Osaka |
N/A |
JP |
|
|
Assignee: |
PANASONIC INTELLECTUAL PROPERTY
MANAGEMENT CO., LTD. (Osaka, JP)
|
Family
ID: |
68061633 |
Appl.
No.: |
17/040,398 |
Filed: |
March 19, 2019 |
PCT
Filed: |
March 19, 2019 |
PCT No.: |
PCT/JP2019/011418 |
371(c)(1),(2),(4) Date: |
September 22, 2020 |
PCT
Pub. No.: |
WO2019/188582 |
PCT
Pub. Date: |
October 03, 2019 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20210066007 A1 |
Mar 4, 2021 |
|
Foreign Application Priority Data
|
|
|
|
|
Mar 28, 2018 [JP] |
|
|
JP2018-063264 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01H
33/78 (20130101); H01H 39/00 (20130101); H01H
33/28 (20130101); H01H 9/30 (20130101); H01H
33/025 (20130101); H01H 9/302 (20130101); H01H
33/56 (20130101); H01H 33/7015 (20130101); H01H
2039/008 (20130101); H01H 37/74 (20130101); H01H
33/72 (20130101); H01H 50/546 (20130101); H01H
1/20 (20130101) |
Current International
Class: |
H01H
33/02 (20060101); H01H 33/70 (20060101); H01H
33/56 (20060101); H01H 33/28 (20060101); H01H
33/78 (20060101) |
Field of
Search: |
;218/49,48,90,95,94,93,92,111 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
928 658 |
|
Jun 1955 |
|
DE |
|
48-008644 |
|
Jan 1973 |
|
JP |
|
59-090323 |
|
May 1984 |
|
JP |
|
61-260528 |
|
Nov 1986 |
|
JP |
|
11-102633 |
|
Apr 1999 |
|
JP |
|
2010-153371 |
|
Jul 2010 |
|
JP |
|
2017-507469 |
|
Mar 2017 |
|
JP |
|
Other References
Official Communication issued in International Patent Application
No. PCT/JP2019/011418, dated Jun. 4, 2019, along with an English
translation thereof. cited by applicant .
Extended European Search Report, dated Sep. 2, 2021, by the
European Patent Office (EPO), for European Patent Application No.
19777142.1. cited by applicant.
|
Primary Examiner: Bolton; William A
Attorney, Agent or Firm: Greenblum & Bernstein,
P.L.C.
Claims
The invention claimed is:
1. A circuit interrupter, comprising: a fixed terminal including a
fixed contact; a movable contactor including a movable contact
connected to the fixed contact; a moving mechanism configured to
move the movable contactor from a closed position where the movable
contact is connected to the fixed contact to an open position where
the movable contact is separated from the fixed contact; a squib
configured to generate gas by combustion; a case accommodating the
squib and having a sleeve; an accommodation for accommodating the
fixed contact and the movable contactor; and a channel provided to
a side wall of the sleeve and connecting between the sleeve and the
accommodation, wherein the moving mechanism includes a piston
accommodated in the sleeve; while the squib generates the gas, the
gas presses the piston from a first position to a second position;
and when the piston is in the second position, the gas is
introduced into the accommodation via the channel.
2. The circuit interrupter according to claim 1, wherein the gas is
introduced into a predetermined space between the fixed contact and
the movable contact while the movable contactor is in the open
position.
3. The circuit interrupter according to claim 2, wherein the gas is
introduced in a direction perpendicular to the predetermined
space.
4. The circuit interrupter according to claim 1, wherein the moving
mechanism further includes a pressurized chamber for receiving
pressure of the gas, the piston receives pressure inside the
pressurized chamber and moves the movable contactor in the closed
position by applying a force to the movable contactor in a
direction toward the open position, and part of the gas is
introduced into the accommodation from the pressurized chamber.
5. The circuit interrupter according to claim 1, wherein the moving
mechanism includes a trip device for moving the movable contactor
from the closed position to the open position in response to an
abnormal current flowing through a circuit including the movable
contact and the fixed contact.
6. The circuit interrupter according to claim 5, wherein the trip
device includes an excitation coil constituting part of the
circuit, and the trip device is configured to move the movable
contactor to the open position by an electromagnetic force
developed by a magnetic flux caused by the excitation coil in
response to a flow of the abnormal current through the circuit.
7. The circuit interrupter according to claim 5, wherein the trip
device includes a bimetallic plate which curves in response to a
flow of the abnormal current through the circuit, and the trip
device is configured to move the movable contactor to the open
position when the bimetallic plate curves in response to the flow
of the abnormal current through the circuit.
8. The circuit interrupter according to claim 1, further
comprising: an elastic part for providing an elastic force in a
direction toward the closed position, to the movable contactor.
9. The circuit interrupter according to claim 1, further
comprising: a permanent magnet for holding the movable contactor in
the closed position.
10. The circuit interrupter according to claim 1, further
comprising: a space which includes the accommodation and in which
the gas is sealed.
11. The circuit interrupter according to claim 1, wherein the
piston is configured to move the movable contactor from the closed
position to the open position by applying a force, and an inner
diameter of the sleeve is tapered so as to become narrower in a
direction from the first position to the second position and
configured to hold the piston to maintain the force on the movable
contactor in the direction toward the open position.
12. A circuit interrupter, comprising: a fixed terminal including a
fixed contact; a movable contactor including a movable contact
connected to the fixed contact; a squib configured to generate gas
by combustion; a first moving mechanism including an excitation
coil configured to move the movable contactor from a closed
position where the movable contact is connected to the fixed
contact to a first open position where the movable contact is
separated from the fixed contact and a shaft with the movable
contact coupled to one end and configured to move inside the
excitation coil in the first open position; and a second moving
mechanism including the squib and configured to move the movable
contactor to a second open position where the movable contact is
separated from the fixed contact to interrupt an abnormal
current.
13. The circuit interrupter according to claim 12, wherein a
distance between the fixed contact and the movable contact in the
second open position is larger than a distance between the fixed
contact and the movable contact in the first open position.
14. A circuit interrupter, comprising: a fixed terminal including a
fixed contact; a movable contactor including a movable contact
connected to the fixed contact; a moving mechanism configured to
move the movable contactor from a closed position where the movable
contact is connected to the fixed contact to an open position where
the movable contact is separated from the fixed contact; a squib
configured to generate gas by combustion; a case accommodating the
squib and having a sleeve; and an accommodation for accommodating
the fixed contact and the movable contactor; wherein the moving
mechanism includes a piston accommodated in the sleeve; the gas
moves the piston from a first position to a second position, and
the piston moves the movable contactor from the closed position to
the open position, when the squib generates the gas; and an inner
diameter of the sleeve is tapered so as to become narrower in a
direction from the first position to the second position and
configured to hold the piston to maintain the force on the movable
contactor in the direction toward the open position.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a National Stage of International Application
No. PCT/JP2019/011418 filed Mar. 19, 2019, claiming priority to
Japanese Patent Application No. JP2018-063264 filed on Mar. 28,
2018, the content of each noted application is hereby incorporated
by reference in its entirety.
TECHNICAL FIELD
The present disclosure generally relates to circuit interrupters
and in particular to a circuit interrupter for interrupting a
circuit where a current flows.
BACKGROUND ART
Patent Literature 1 discloses a breaker including a pyrotechnic
actuator which is intended to be mounted on an automobile, in
particular, an electric vehicle.
The breaker of Patent Literature 1 includes a conductor, a housing,
a matrix, a punch, and a pyrotechnic actuator.
The housing is partially intersected by the conductor. Opposite
ends of the conductor serve as two connection terminals for the
breaker. The matrix and the punch are placed on opposite sides
(upper and lower sides) of the conductor.
The pyrotechnic actuator moves the punch from a first position to a
second position when ignited. In movement of the punch from the
first position to the second position, the punch, and the matrix
break (chop) the conductor. The punch includes a groove. While the
punch is in the second position, the groove of the punch is engaged
with the matrix. Thereby, a space inside the housing is partitioned
into two cutoff chambers.
When the punch moves from the first position to the second position
and cuts the conductor, an electric arc may be formed. This
electric arc travels a pathway between the cutoff chamber and a
bottom of the groove of the punch. To increase a voltage of the
electric arc, provided to a vicinity of the pathway is a material
pulled out by ablation due to the electric arc.
In interrupters such as breakers, it is desired to extinguish an
arc rapidly.
CITATION LIST
Patent Literature
Patent Literature 1 JP 2017-507469 A
SUMMARY OF INVENTION
In view of the above insufficiency, an object of the present
disclosure would be to propose a circuit interrupter capable of
extinguishing an arc quickly when the arc is developed.
A circuit interrupter according to one aspect of the present
disclosure includes a fixed terminal, a movable contactor, a moving
mechanism, a squib, and accommodation. The fixed terminal includes
a fixed contact. The movable contactor includes a movable contact
connected to the fixed contact. The moving mechanism is configured
to move the movable contactor from a closed position where the
movable contact is connected to the fixed contact to an open
position where the movable contact is separated from the fixed
contact. The squib is configured to generate gas by combustion. The
accommodation is for accommodating the fixed contact and the
movable contactor. The gas is introduced into the
accommodation.
A circuit interrupter according to another aspect of the present
disclosure includes a fixed terminal, a movable contactor, an
excitation coil, and a moving mechanism. The fixed terminal
includes a fixed contact. The movable contactor includes a movable
contact connected to the fixed contact. The squib is configured to
generate gas by combustion. The excitation coil is configured to
move the movable contactor from a closed position where the movable
contact is connected to the fixed contact to a first open position
where the movable contact is separated from the fixed contact. The
moving mechanism is configured to move the movable contactor to a
second open position where the movable contact is separated from
the fixed contact.
Advantageous Effects of Invention
According to the present disclosure, it is possible to extinguish
an arc quickly when the arc is developed.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a cross-sectional view of a circuit interrupter according
to embodiment 1 of the present disclosure.
FIG. 2 is a perspective view of primary part of the above circuit
interrupter.
FIG. 3 is a cross-sectional view in a direction perpendicular to
the sheet of FIG. 1, of the above circuit interrupter.
FIG. 4 is a cross-sectional view of a pyroactuator included in the
above circuit interrupter.
FIG. 5 is a circuit diagram for illustration of a power supply
system including the above circuit interrupter.
FIG. 6 is a cross-sectional view of the above circuit interrupter
in operation.
FIG. 7 is a cross-sectional view of the above circuit interrupter
after operation.
FIGS. 8A-8C are diagrams for illustration of stretch of an arc by a
gas in the above circuit interrupter.
FIG. 9 is a cross-sectional view of a circuit interrupter of one
variation according to embodiment 1.
FIG. 10 is a cross-sectional view of the above circuit interrupter
after operation.
FIG. 11 is a cross-sectional view of a circuit interrupter of
embodiment 2.
FIG. 12 is a cross-sectional view of the above circuit interrupter
after operation.
FIG. 13 is a side view of a circuit interrupter of variation 1
according to embodiment 2.
FIG. 14 is a side view in a direction perpendicular to the sheet of
FIG. 13, of the above circuit interrupter after operation.
FIG. 15 is a side view of the above circuit interrupter after
operation.
FIG. 16 is a cross-sectional view of a circuit interrupter of
variation 2 according to embodiment 2.
FIG. 17 is a perspective view of a movable contactor of the above
circuit interrupter.
FIG. 18 is a cross-sectional view of a circuit interrupter of
variation 3 according to embodiment 2.
FIG. 19 is a cross-sectional view of a circuit interrupter of
concrete example 1.
FIG. 20 is a cross-sectional view of the above circuit interrupter
in its off state.
FIG. 21 is a cross-sectional view of the above circuit interrupter
after operation.
FIG. 22 is a cross-sectional view of a circuit interrupter of
concrete example 2.
FIG. 23 is a cross-sectional view of the above circuit interrupter
in its off state.
FIG. 24 is a cross-sectional view of a circuit interrupter of
concrete example 3.
FIG. 25 is a cross-sectional view of the above circuit interrupter
after operation.
FIG. 26 is a cross-sectional view of a circuit interrupter of
concrete example 4.
FIG. 27 is a cross-sectional view of the above circuit interrupter
in its off state.
FIG. 28 is a cross-sectional view of the above circuit interrupter
after operation.
FIG. 29 is a cross-sectional view of a circuit interrupter of
concrete example 5.
FIG. 30 is a cross-sectional view of the above circuit interrupter
in its off state.
FIG. 31 is a cross-sectional view of the above circuit interrupter
after operation.
DESCRIPTION OF EMBODIMENTS
Embodiments and variations described below are some of example of
the present disclosure. Various modifications may be made to the
above-described embodiment and variations depending on design and
the like as long as the object of the present disclosure can be
achieved. Figures referred to in the following embodiments and
variations are schematic, and there is no guarantee that ratios
regarding sizes and thicknesses of components shown in the figures
reflect actual ratios.
(1) Embodiments
A circuit interrupter (current interrupter) 100 according to
embodiment 1 will be described with reference to FIGS. 1-7.
(1.1) Overview
The circuit interrupter 100 according to embodiment 1 includes, as
shown in FIG. 1, a first fixed terminal (fixed terminal) 1, a
second fixed terminal 2, a movable contactor (movable terminal) 3,
a holding unit 4, a pyroactuator 5, and an accommodation 70.
The first fixed terminal 1 includes a first fixed contact (fixed
contact) 11. The first fixed terminal 1 includes a first electrode
12 to be connected to a first end of electric circuitry.
The second fixed terminal 2 includes a second fixed contact 21. The
second fixed terminal 2 includes a second electrode 22 to be
connected to a second end of the electric circuitry.
The movable contactor 3 includes a first movable contact (movable
contact) 31. The first movable contact 31 is connected to the first
fixed contact 11. The movable contactor 3 includes a second movable
contact 32. The second movable contact 32 is connected to the
second fixed contact 21. In the present embodiment, the movable
contactor 3 is formed as a separate part from each of the first
fixed terminal 1 and the second fixed terminal 2.
The first fixed contact 11, the second fixed contact 21, and the
movable contactor 3 (the first movable contact 31 and the second
movable contact 32) are accommodated in the accommodation 70.
The holding unit 4 holds the movable contactor 3 so that the first
movable contact 31 is connected to the first fixed contact 11 and
the second movable contact 32 is connected to the second fixed
contact 21. In particular, the holding unit 4 holds the movable
contactor 3 so that the first movable contact 31 and the second
movable contact 32 are connected to the first fixed contact 11 and
the second fixed contact 21, respectively, while no current flows
through the movable contactor 3 (during a non-conduction
state).
Hereinafter, a position of the movable contactor 3 where the first
movable contact 31 is connected to the first fixed contact 11 is
referred to as a closed position. In the closed position, the
second movable contact 32 is connected to the second fixed contact
21, too.
As shown in FIG. 1, the pyroactuator 5 includes a squib 51, a case
52, and a piston 53.
The squib 51 is accommodated in the case 52. The squib 51 is
configured to generate gas by combustion. The squib 51 includes a
heating element and an explosive (fuel). When the heating element
is supplied with an electric signal, the heating element generates
heat and then the explosive ignites. When the squib 51 is ignited,
the explosive combusts to generate gas. The gas generated by the
squib 51 has electrically insulating properties. Examples of the
gas generated by the squib 51 may include a carbon monoxide gas, a
carbon dioxide gas, and a nitrogen gas. The gas generated by the
squib 51 is introduced into the pressurized chamber 520 to increase
the pressure in the pressurized chamber 520. In summary, the
pressurized chamber 520 receives the pressure of the gas generated
by the squib 51.
The piston 53 receives pressure in the pressurized chamber 520 with
its first end 531 and then is moved. The piston 53 applies a force
in a direction away from the fixed terminal (the first fixed
terminal) 1 to the movable contactor 3 (directly or indirectly)
with its second end 532 to cause movement of the movable contactor
3. More specifically, the piston 53 receives the pressure of the
pressurized chamber 520 with the first end 531 and is pressed by
the increased pressure in the pressurized chamber 520 to press the
movable contactor 3 with the second end 532. The piston 53 receives
a large pressure in the pressurized chamber 520 and moves in a
direction away from the squib 51 (a downward direction in FIG. 1)
at a high speed to press the movable contactor 3. The pressure in
the pressurized chamber 520 presses the piston 53 from a first
position (a position shown in FIG. 1) to a second position (a
position shown in FIG. 7). Movement of the piston 53 from the first
position to the second position expands the pressurized chamber 520
(a space inside the case 52 pressure of which is increased by
introduction of the gas of the squib 51).
The movable contactor 3 is pressed by the piston 53 and then moves
within the accommodation 70. As shown in FIGS. 6-7, the movable
contactor 3 is pressed by the piston 53 and therefore the first
movable contact 31 is separated from the first fixed contact 11 and
the second movable contact 32 is separated from the second fixed
contact 21. Thus, an electric circuit between the first electrode
12 and the second electrode 22 is interrupted. As described above,
in the present embodiment, the pressurized chamber 520 and the
piston 53 function as a moving mechanism configured to move the
movable contactor 3 from a position where the movable contact
(first movable contact) 31 is connected to the fixed contact (first
fixed contact) 11 to a position where the movable contact is
separated from the fixed contact.
Hereinafter, a position of the movable contactor 3 where the first
movable contact 31 is most separated from the first fixed contact
11 is referred to as an open position (a position of the movable
contactor 3 shown in FIG. 7). In the open position, the second
movable contact 32 is separated from the second fixed contact 21,
too.
As shown in FIG. 1, there is a channel 50 provided to the side wall
of the case 52. The channel 50 interconnects the inside and the
outside of the case 52. The channel 50 includes a first end 501
connected to the accommodation 70 and a second end 502 connected to
the inside space of the case 52. However, while the piston 53 is in
the first position, the second end 502 of the channel 50 is not
connected to the pressurized chamber 520 (see FIG. 1).
Movement of the piston 53 from the first position (see FIG. 1) to
the second position (see FIG. 7) extends the pressurized chamber
520, thereby allowing the second end 502 of the channel 50 to be
connected to the pressurized chamber 520. As a result, the
pressurized chamber 520 and the accommodation 70 are interconnected
by the channel 50. Therefore, the gas generated by the squib 51 is
introduced into the accommodation 70 through the pressurized
chamber 520 and the channel 50.
The first fixed contact 11 and the first movable contact 31 are
accommodated in the accommodation 70. Here, as described above, the
gas generated by the squib 51 is introduced into the accommodation
70 Thus, the arc generated between the fixed contact (first fixed
contact) 11 and the movable contact (first movable contact) 31
(i.e., the arc generated in the predetermined space S1) is cooled
by the gas generated in the squib 51. The term "cooling of the arc"
as used herein means to enhance the insulating properties of the
plasma of the arc discharge or the metal vapor. For example,
cooling of the arc can be achieved by increasing the pressure of
the predetermined space S1 by introduction of electrically
insulating gas, blowing the arc with electrically insulating gas,
or the like. When the arc is cooled, an electric field strength of
the arc (a voltage per unit length) is increased. This can reduce
the length of the arc that is possibly developed when a certain
constant voltage is applied across the arc. Thereby, arc extinction
can be promoted.
Thus, in the circuit interrupter 100, when the movable contact
(first movable contact) 31 is pulled away from the fixed contact
(first fixed contact) 11, the gas generated by the squib 51 is
introduced into the accommodation 70 (in detail, the predetermined
space S1). When the arc is developed between the contacts, the arc
is cooled by the gas. Accordingly, the circuit interrupter 100 can
quickly extinguish the arc.
(1.2) Details
Hereinafter, the circuit interrupter 100 according to the present
embodiment will be described in detail with reference to FIGS.
1-7.
(1.2.1) Power Supply System
As shown in FIG. 5, the circuit interrupter 100 of the present
embodiment is used, for example, as a fuse in the power supply
system 200.
The power supply system 200, for example, is mounted on a vehicle
300 such as an electric vehicle and drives a motor 3002 connected
via an inverter 3001 to allow the vehicle 300 to run. In the
vehicle 300, as shown in FIG. 5, a precharge capacitor 3003 is
connected in parallel with the inverter 3001.
In power transfer, the inverter 3001 converts DC power supplied
from the power supply system 200 into AC power and supplies it to
the motor 3002. In power regeneration, the inverter 3001 converts
AC power supplied from the motor 3002 into DC power and supplies it
to the power supply system 200. The motor 3002 is, for example, a
three-phase AC synchronous motor.
The power supply system 200 includes a battery 201, a first main
relay 202, a second main relay 203, a precharge resistor 204, a
precharge relay 205, a current sensor (shunt resistor) 206, and
control circuitry 207 in addition to the circuit interrupter
100.
The battery 201 includes a plurality of battery cells connected in
series. Examples of the battery cells may include nickel metal
hydride battery cells and lithium ion battery cells.
The first main relay 202 includes a first end connected to a
positive electrode of the battery 201 and a second end connected to
a first input terminal (high potential side input terminal) of the
inverter 3001.
The second main relay 203 includes a first end connected to a
negative electrode of the battery 201 through the current sensor
206 and the circuit interrupter 100 and a second end connected to a
second input terminal (low potential side input terminal) of the
inverter 3001.
A series circuit of the precharge resistor 204 and the precharge
relay 205 is connected in parallel with the first main relay
202.
The control circuitry 207 controls operations of the first main
relay 202, the second main relay 203, the precharge relay 205, and
the circuit interrupter 100.
When power supply to the motor 3002 is started, the control
circuitry 207 closes the precharge relay 205 and the second main
relay 203 to charge the precharge capacitor 3003. Thus, inrush
current to the motor 3002 is suppressed. After completion of
charging of the precharge capacitor 3003, the control circuitry 207
opens the precharge relay 205 and closes the first main relay 202
to start power supply from the power supply system 200.
The control circuitry 207 also detects occurrence of an abnormality
in circuitry including the power supply system 200 based on a
current detected by the current sensor 206. When an abnormality
occurs in the circuitry including the power supply system 200, the
control circuitry 207 operates (activates) at least one of the
first main relay 202, the second main relay 203, and the circuit
interrupter 100 to interrupt the circuitry.
The control circuitry 207 opens at least one of the first main
relay 202 and the second main relay 203 when, for example, time in
which the magnitude of the current detected by the current sensor
206 exceeds a first threshold value continues for first time.
Thereby the circuitry is interrupted. In this case, for example,
when the opened relay (the first main relay 202 and/or the second
main relay 203) is closed again by the control circuitry 207, the
circuitry is made again and therefore the power supply from the
power supply system 200 to the motor 3002 is resumed.
On the other hand, for example, when time in which the magnitude of
the current detected by the current sensor 206 exceeds a second
threshold value (>the first threshold value) continues for
second time, the control circuitry 207 operates the circuit
interrupter 100. Thereby, the circuitry is interrupted. The circuit
interrupter 100 is a breaker for breaking an electrical circuit
(path) of circuitry. The circuit interrupter 100 continues to break
the electric circuit once operated (activated). After activation of
the circuit interrupter 100, the power supply from the power supply
system 200 to the motor 3002 is stopped. Therefore, in the event of
an accident or the like of the vehicle 300, operation of the
circuit interrupter 100 can separate the power supply system
200.
(1.2.2) Configuration
Next, the configuration of the circuit interrupter 100 will be
described with reference to FIGS. 1-4.
As described above, the circuit interrupter 100 includes the first
fixed terminal 1, the second fixed terminal 2, the movable
contactor 3, the holding unit 4, and the pyroactuator 5. Further,
as shown in FIG. 1, the circuit interrupter 100 includes a first
yoke (lower yoke) 61, a second yoke (upper yoke) 62, and a housing
7 including the accommodation 70.
The movable contactor 3 of the present embodiment is a plate member
made of a metallic material with electrical conductivity and is
formed to have length in one direction. The movable contactor 3
includes the first movable contact 31 and the second movable
contact 32 at respective first and second ends in its length
direction. The first fixed terminal 1 and the second fixed terminal
2 are arranged side by side along the length direction of the
movable contactor 3. The first fixed terminal 1 includes the first
fixed contact 11 at a position facing the first movable contact 31
of the movable contactor 3 and the second fixed terminal 2 includes
the second fixed contact 21 at a position facing the second movable
contact 32 of the movable contactor 3.
Hereinafter, for convenience of explanation, an upward/downward
direction defines a direction in which the first fixed contact 11
and the first movable contact 31 face each other (a direction in
which the second fixed contact 21 and the second movable contact 32
face each other; an upward/downward direction in FIG. 1) and an
upward direction defines a direction from the first movable contact
31 toward the first fixed contact 11. Further, a rightward/leftward
direction defines a direction in which the first fixed terminal 1
and the second fixed terminal 2 are aligned side by side (a
rightward/leftward direction in FIG. 1) and a rightward direction
defines a direction from the first fixed terminal 1 toward the
second fixed terminal 2. That is to say, in the following
description, the upward, downward, rightward, and leftward
directions are supposed to be defined on the basis of the
directions shown in FIG. 1. Furthermore, in the following
description, a direction perpendicular to both the upward/downward
direction and the rightward/leftward direction (i.e., the direction
coming out of the paper on which FIG. 1 is depicted) is defined
herein to be a forward/backward direction. However, these
directions are not intended to limit the usage of the circuit
interrupter 100.
The first fixed terminal 1 and the second fixed terminal 2 are
placed to be arranged side by side in the rightward/leftward
direction (see FIG. 1). Each of the first fixed terminal 1 and the
second fixed terminal 2 is made of a metallic material with
electrical conductivity. The first fixed terminal 1 and the second
fixed terminal 2 function as terminals for connecting the external
electric circuitry (the circuitry constituting the power supply
system 200) to the first fixed contact 11 and the second fixed
contact 21. In the present embodiment, each of the first fixed
terminal 1 and the second fixed terminal 2 is made of copper (Cu)
as an example. However, not limited thereto, each of the first
fixed terminal 1 and the second fixed terminal 2 may be made of an
electrically conductive material other than copper.
As shown in FIG. 2, the first fixed terminal 1 includes a
connection piece 110, an electrode piece 120, an interconnection
piece 130, and a circuit piece 140 which are formed as an integral
part.
The connection piece 110 has a rectangular plate shape with a
thickness in the upward/downward direction and a length in the
forward/backward direction. In the present embodiment, a lower
surface of the connection piece 110 functions as the first fixed
contact 11 but is not limited thereto. The first fixed contact 11,
for example, may be made of a separate member from the connection
piece 110 and fixed to the connection piece 110 by welding or the
like.
The electrode piece 120 has a plate shape with a thickness in the
forward/backward direction. The electrode piece 120 has a square
shape and includes a through hole in its center. The electrode
piece 120 is configured to be connected to the first end of the
external electric circuitry. That is, the electrode piece 120
functions as the first electrode 12 to be connected to the first
end of the external electric circuitry.
The interconnection piece 130 has a rectangular plate shape with a
thickness in the rightward/leftward direction and a length in the
upward/downward direction. A lower side of the interconnection
piece 130 is connected to a left side of the connection piece
110.
The circuit piece 140 has a plate shape with a thickness in the
forward/backward direction. The circuit piece 140 interconnects the
electrode piece 120 and the interconnection piece 130. A left side
of the circuit piece 140 is coupled to an upper portion of a right
side of the electrode piece 120. The right side of the circuit
piece 140 is coupled to a center of a left surface of the
interconnection piece 130.
As shown in FIG. 2, the second fixed terminal 2 includes a
connection piece 210, an electrode piece 220, an interconnection
piece 230, and a circuit piece 240 which are formed as an integral
part.
The connection piece 210 has a rectangular plate shape with a
thickness in the upward/downward direction and a length in the
forward/backward direction. In the present embodiment, a lower
surface of the connection piece 210 functions as the second fixed
contact 21 but is not limited thereto. The second fixed contact 21,
for example, may be made of a separate member from the connection
piece 210 and fixed to the connection piece 210 by welding or the
like.
The electrode piece 220 has a plate shape with a thickness in the
forward/backward direction. The electrode piece 220 has a square
shape and includes a through hole in its center. The electrode
piece 220 is configured to be connected to the second end of the
external electric circuitry. That is, the electrode piece 220
functions as the second electrode 22 to be connected to the second
end of the external electric circuitry.
The interconnection piece 230 has a rectangular plate shape with a
thickness in the rightward/leftward direction and a length in the
upward/downward direction. A lower side of the interconnection
piece 230 is coupled to a right side of the connection piece
210.
The circuit piece 240 has a plate shape with a thickness in the
forward/backward direction. The circuit piece 240 interconnects the
electrode piece 220 and the interconnection piece 230. The right
side of the circuit piece 240 is coupled to an upper portion of the
left side of the electrode piece 220. The left side of the circuit
piece 240 is coupled to a center of a right surface of the
interconnection piece 230.
As shown in FIG. 1, the first fixed terminal 1 is fixed to the
housing 7 so that the electrode piece 120 protrudes outside from a
left wall of the housing 7 and a lower end of the interconnection
piece 130 and the connection piece 110 are placed in an inside
space of the housing 7 (the accommodation 70). The second fixed
terminal 2 is fixed to the housing 7 so that the electrode piece
220 protrudes outside from a right wall of the housing 7 and a
lower end of the interconnection piece 230 and the connection piece
210 are placed in the inside space of the housing 7 (the
accommodation 70).
As shown in FIGS. 1-3, the movable contactor 3 has a plate shape
which has a thickness in the upward/downward direction and is lager
in the rightward/leftward direction than in the forward/backward
direction. The movable contactor 3 is placed below the connection
piece 110 and the connection piece 210 to allow its opposite ends
in a length direction (the rightward/leftward direction to face (be
connected to) the first fixed contact 11 and the second fixed
contact 21. The first movable contact 31 is provided to a part of
the movable contactor 3 which faces the first fixed contact 11 and
the second movable contact 32 is provided to a part of the movable
contactor 3 which faces the second fixed contact 21 (see FIG.
1).
In the present embodiment, the first movable contact 31 is in
contact with the first fixed contact 11. More particularly, the
first movable contact 31 is in surface contact with the first fixed
contact 11. The second movable contact 32 is in contact with the
second fixed contact 21. More particularly, the second movable
contact 32 is in surface contact with the second fixed contact
21.
In the present embodiment, the first movable contact 31 is a
separate member from the movable contactor 3, is made of silver
(Ag), and is fixed to the movable contactor 3 by welding or the
like. Similarly, the second movable contact 32 is a separate member
from the movable contactor 3, is made of silver (Ag) and is fixed
to the movable contactor 3 by welding or the like. However, not
limited thereto, each of the first movable contact 31 and the
second movable contact 32 may be formed integrally with the movable
contactor 3 by striking the movable contactor 3 partially.
As shown in FIG. 1, the movable contactor 3 is accommodated in the
inside space of the housing 7 (the accommodation 70). The movable
contactor 3 is held by the holding unit 4 so that the first movable
contact 31 and the second movable contact 32 are connected to the
first fixed contact 11 and the second fixed contact 21,
respectively.
The first fixed terminal 1 and the second fixed terminal 2 are
short-circuited through the movable contactor 3. That is, the first
electrode 12 of the first fixed terminal 1 is electrically
connected to the second electrode 22 of the second fixed terminal 2
through the first fixed contact 11, the first movable contact 31,
the movable contactor 3, the second movable contact 32 and the
second fixed contact 21 (see FIG. 2). Therefore, when the first
electrode 12 and the second electrode 22 are electrically connected
to the first end and the second end of the electric circuitry
respectively, the circuit interrupter 100 forms an electric path
between the first electrode 12 and the second electrode 22.
As shown in FIGS. 1, 3, the housing 7 includes an inner hollow
cylinder 71, an outer hollow cylinder 72, and a cover member
73.
The inner hollow cylinder 71 is made of a material having
electrically insulating properties, for example, a resin material.
The inner hollow cylinder 71 has a bottomed hollow circular
cylindrical shape with a closed lower surface and an open upper
surface. A holding rib 711 which has a hollow circular cylindrical
shape is provided to an upper surface of a lower wall of the inner
hollow cylinder 71 (a bottom surface of the inner hollow cylinder
71). The holding rib 711 is formed concentrically with the inner
hollow cylinder 71.
The outer hollow cylinder 72 is made of, for example, a metal
material. The outer hollow cylinder 72 is preferably made of a
non-magnetic metal material. Examples of the non-magnetic metallic
material may include an austenitic stainless steel such as SUS304.
However, the material of the outer hollow cylinder 72 may not be
non-magnetic and may be, for example, an alloy containing iron as a
main component, such as 42 alloy.
The outer hollow cylinder 72 is concentric with the inner hollow
cylinder 71 and has a bottomed hollow circular cylindrical shape
with a closed lower surface and an open upper surface. The outer
hollow cylinder 72 is provided to surround a periphery of the inner
hollow cylinder 71. In other words, the outer hollow cylinder 72 is
a strength member for improving the strength of the housing 7 (the
strength of an outer wall of the accommodation 70).
The inner hollow cylinder 71 may be integrally formed with the
outer hollow cylinder 72 by, for example, insert molding or the
like. The housing 7 may not include the outer hollow cylinder
72.
The cover member 73 is made of a material having electrically
insulating properties, for example, a resin material. The cover
member 73 has a bottomed hollow cylindrical shape with a closed
upper surface and a lower surface having an opening. The cover
member 73, for example, may be formed integrally with the first
fixed terminal 1 and the second fixed terminal 2 by insert
molding.
A thickness of an upper wall of the cover member 73 is larger than
a thickness of a side wall of the cover member 73. A through hole
731 which is concentric with the cover member 73 is formed in a
center of the upper wall of the cover member 73. The pyroactuator 5
is placed inside the through hole 731 of the cover member 73. A
lower end of the pyroactuator 5 protrudes from a lower surface
(inner surface) of the upper wall of the cover member 73. The
through hole 731 is hermetically closed by the pyroactuator 5 (a
case 52 thereof).
An annular recessed groove 732 is formed in a lower surface of the
side wall of the cover member 73. By inserting upper edges of the
inner hollow cylinder 71 and the outer hollow cylinder 72 into the
recessed groove 732, the inner hollow cylinder 71 and the outer
hollow cylinder 72 are coupled to the cover member 73. As a result,
the housing 7 has the airtight inside space (the accommodation 70)
surrounded by the inner hollow cylinder 71 and the cover member 73.
The first fixed contact 11, the second fixed contact 21, and the
movable contactor 3 are accommodated in the inside space (the
accommodation 70) of the housing 7.
In the present embodiment, the shape of the housing 7 is a
substantially circular cylindrical shape having an inside space
(the accommodation 70) but may not be limited thereto. It is
sufficient that the housing 7 has any shape as long as it has an
inside space (the accommodation 70) for accommodating the first
fixed contact 11, the second fixed contact 21, and the movable
contactor 3. The housing 7 may have another shape such as a hollow
polygonal prism (for example, a hollow rectangular parallelepiped
shape).
The first yoke 61 is a ferromagnetic body and may be made of a
metallic material such as iron. The first yoke 61 is fixed to the
lower surface of the movable contactor 3 and is integral with the
movable contactor 3 (see FIGS. 1, 3). That is, the first yoke 61 is
fixed to an opposite surface of the movable contactor 3 from a
surface where the first movable contact 31 and the second movable
contact 32 are placed.
When a current flows through the movable contactor 3, the first
yoke 61 allows a magnetic field caused by the current to pass
through the first yoke 61. That is, when the first yoke 61 is not
provided, the (concentric) magnetic field around the current
flowing through the movable contactor 3 is generated. When the
first yoke 61 is provided, the magnetic field is changed so as to
pass through the first yoke 61. Therefore, the center of the
magnetic field acting on the current flowing through the movable
contactor 3 is attracted toward the surface where the first movable
contact 31 and the second movable contact 32 are placed (i.e., the
upper surface). As a result, a relatively upward force is generated
in the movable contactor 3. Therefore, the connection between the
pair of the first movable contact 31 and the second movable contact
32 and the pair of the first fixed contact 11 and the second fixed
contact 21 are more easily maintained in a case where the first
yoke 61 is provided than in a case where the first yoke 61 is not
provided.
An engagement recess 610 which is a circular cylindrical recess is
formed in a lower surface of the first yoke 61.
The second yoke 62 is a ferromagnetic body and may be made of a
metallic material such as iron. The second yoke 62 is positioned
and fixed at a position facing the first yoke 61 with the movable
contactor 3 in-between and is separated from the movable contactor
3. The second yoke 62 may be in contact with the second end 532
(lower end) of the piston 53 of the pyroactuator 5. In this
embodiment, the second yoke 62 is fixed to the second end 532
(lower end) of the piston 53 of the pyroactuator 5. The second yoke
62 is placed to face the center of the movable contactor 3 (see
FIG. 2) but not to be in contact with the movable contactor 3 by a
gap (see FIG. 3). The second yoke 62 is electrically insulated from
the movable contactor 3.
The second yoke 62 includes a pair of protrusion parts 621, 622
(see FIG. 3) protruding in the upward direction at its both ends in
the forward/backward direction. In other words, formed on both ends
in the forward/backward direction of the upper surface of the
second yoke 62 are the protrusion parts 621, 622 respectively
facing the side surface in the forward/backward direction of the
movable contactor 3. As shown in FIG. 3, a distal end surface
(lower end surface) of the protrusion part 621 which is a front one
of the pair of protrusion parts 621,622 faces a front end of the
first yoke 61 and a distal end surface (lower end surface) of the
protrusion part 622 which is a back one of the pair faces a back
end of the first yoke 61. Therefore, when a current flows between
the first fixed terminal 1 and the second fixed terminal 2 through
the movable contactor 3, a magnetic flux passing through a magnetic
path formed by the first yoke 61 and the second yoke 62 is
developed. At this time, the front end of the first yoke 61 and the
protrusion part 621 at the front end of the second yoke 62 are
magnetized to have different polarities. The back end of the first
yoke 61 and the protrusion part 622 at the back end of the second
yoke 62 are magnetized to have different polarities. As a result,
an attraction force acts between the first yoke 61 and the second
yoke 62. The second yoke 62 is fixed to the second end 532 (lower
end) of the piston 53 and therefore the attraction force moves the
first yoke 61 in the upward direction. When the first yoke 61 is
move in the upward direction, an upward force is applied to the
movable contactor 3 by the first yoke 61.
While a current flows through the movable contactor 3, this current
may cause an electromagnetic repulsive force separating the first
movable contact 31 and the second movable contact 32 from the first
fixed contact 11 and the second fixed contact 21. That is, when a
current flows through the movable contactor 3, the Lorentz force
may cause the electromagnetic repulsive force, which moves the
movable contactor 3 downward, on the movable contactor 3.
In the present embodiment, as described above, the magnetic field
is changed by the first yoke 61 to pass through the first yoke 61
and therefore an upward force is generated in contrast to a case
where the first yoke 61 is not provided. The above-mentioned
attraction force acts between the first yoke 61 and the second yoke
62. Consequently, the current flowing through the movable contactor
3 causes a force moving the movable contactor 3 upward, i.e. a
force pressing the first movable contact 31 and the second movable
contact 32 onto the first fixed contact 11 and the second fixed
contact 21, respectively.
As described above, the first yoke 61 and the second yoke 62 serves
as a connection maintenance mechanism which produces a force
maintaining the connection between the pair of the first movable
contact 31 and the second movable contact 32 and the pair of the
first fixed contact 11 and the second fixed contact 21 by using a
current flowing through the movable contactor 3.
Placed between the protrusion parts 621, 622 of the second yoke 62
and the both ends in the forward/backward direction of the upper
surface of the first yoke 61 are spacers 631, 632 made of a
material having electrically insulating properties, for example, a
resin material (see FIG. 3). Thus, the electrically insulating
properties between the second yoke 62 and the first yoke 61 are
ensured.
As shown in FIGS. 1, 3, the holding unit 4 of the present
embodiment includes a contact pressure spring 41. The contact
pressure spring 41 is a coil spring. The contact pressure spring 41
is placed between the bottom surface (inner surface) of the inner
hollow cylinder 71 and the lower surface of the first yoke 61. The
contact pressure spring 41 has a coil axis extending along the
upward/downward direction. The holding rib 711 of the inner hollow
cylinder 71 is inserted into an inside of a first end 411 of the
contact pressure spring 41. A second end 412 of the contact
pressure spring 41 is inserted into the engagement recess 610 of
the first yoke 61. The contact pressure spring 41 gives an upward
elastic force to the movable contactor 3 via the first yoke 61.
That is, the circuit interrupter 100 includes as the holding unit 4
an elastic part (the contact pressure spring 41) for providing to
the movable contactor 3 an elastic force in a direction in which
the movable contact (first movable contact) 31 is connected to the
fixed contact (first fixed contact) 11 (in a direction toward the
closed position).
The contact pressure spring 41 presses the movable contactor 3 in
the upward direction through the first yoke 61. The contact
pressure spring 41 holds the movable contactor 3 so that the first
movable contact 31 is connected to the first fixed contact 11 and
the second movable contact 32 is connected to the second fixed
contact 21.
FIG. 4 shows a cross-sectional view of the pyroactuator 5 of the
present embodiment. The pyroactuator 5 of the present embodiment
has a so-called pin pusher structure configured to push out the
piston 53 (the pin 535) by use of gas generated in the squib
51.
As shown in FIG. 4, the pyroactuator 5 includes the squib 51, a
case 52 having the pressurized chamber 520 therein, and the piston
53.
The squib 51 includes a body 511, a metal sleeve (metal CAN) 512, a
combustion part 513, a pair of pin electrodes 514, and a heating
element 515.
The body 511 is made of, for example, a resin material or the like
having electrically insulating properties and has a bottomed hollow
circular cylindrical shape with an open upper surface and a closed
lower surface. The inside space S110 of the body 511 is sealed with
a sealing material having electrically insulating properties such
as glass.
The metal sleeve 512 is made of metal such as stainless steel, for
example, and includes a hollow circular cylindrical part having a
bottomed hollow circular cylinder with an open upper surface and a
closed lower surface and a flange part protruding laterally from an
upper end of the hollow circular cylindrical part, which are formed
integrally. Formed in a center of a lower wall of the metal sleeve
512 (the hollow circular cylindrical part thereof) is a cross
groove with a depth not penetrating through the lower wall or the
like. That is, a portion of the lower wall of the metal sleeve 512
serves as a lower strength portion which is lower in strength (more
easily broken) than the other portion of the metal sleeve 512. The
metal sleeve 512 is coupled to the body 511 at the flange with bond
to cover the lower surface of the body 511.
The combustion part 513 includes an explosive such as
nitrocellulose, for example. The combustion part 513 is placed in a
space surrounded by the body 511 and the metal sleeve 512. The
explosive contained in the combustion part 513 may be any material
that generates an electrically insulating gas by combustion and is
not limited to nitrocellulose.
Each of the pair of pin electrodes 514 has a first end positioned
within the combustion part 513 (in the space surrounded by the body
511 and the metal sleeve 512) and a second end exposed outside the
pyroactuator 5 through the body 511. The second ends of the pair of
pin electrodes 514 are connected to the control circuitry 207.
The heating element 515 is an element that generates heat by
energization. In the present embodiment, the heating element 515 is
a nichrome wire. The heating element 515 is placed in the
combustion part 513 (the space surrounded by the body 511 and the
metal sleeve 512). The heating element 515 is connected between the
first ends of the pair of pin electrodes 514.
In the squib 51, when a current from the control circuitry 207
flows between the pair of pin electrodes 514, the heating element
515 generates heat and this causes increase in the temperature of
the combustion part 513. When the temperature of the combustion
part 513 (a surrounding part of the heating element 515) exceeds an
ignition temperature, the explosive combusts explosively to
generate a large amount of gas (for example, carbon monoxide gas,
carbon dioxide gas, nitrogen gas) instantaneously. When the
pressure in the combustion part 513 exceeds a withstand pressure of
the low strength portion of the metal sleeve 512 due to generation
of gas, the low strength portion is broken and the gas generated by
combustion is discharged to the outside (in this embodiment, the
lower pressurized chamber 520) through the broken portion.
As shown in FIG. 4, the piston 53 includes a base 533, a cylinder
534, the pin (rod) 535, and a spring 536.
The base 533 is formed of an electrically insulating material such
as, for example, resin, and is made of, for example, polycarbonate
or polybutylene terephthalate. The base 533 includes a first
columnar section, a second columnar section, and a third columnar
section in this order from the top each of which has a circular
cylindrical shape. The first columnar section, the second columnar
section, and the third columnar section are connected
(concentrically) in the upward/downward direction with their axes
being aligned. An outer diameter of the first columnar section is
larger than an outer diameter of the second columnar section and
the outer diameter of the second columnar section is larger than an
outer diameter of the third columnar section. An annular holding
groove 5330 which is concentric with the first columnar section and
the second columnar section is formed at a boundary between the
first columnar section and the second columnar section on an outer
side surface of the base 533.
In the present embodiment, a bottom surface (upper surface) of the
first columnar section of the base 533 serves as the first end 531
of the piston 53.
The cylinder 534 is made of an electrically insulating material
such as resin. The cylinder 534 is formed in a hollow circular
cylindrical shape. An inner diameter of the cylinder 534 is
approximately equal to the outer diameter of the third columnar
section of the base 533 but is smaller than the outer diameter of
the second columnar section of the base 533. The outer diameter of
the cylinder 534 is smaller than the outer diameter of the second
columnar section of the base 533. The third columnar section of the
base 533 is fitted into an opening in the upper surface of the
cylinder 534 and thus the cylinder 534 and the base 533 are coupled
to each other.
The pin 535 is made of an electrically insulating material such as,
for example, resin, and is made of, for example, polycarbonate or
polybutylene terephthalate. The pin 535 includes a large diameter
portion and a small diameter portion in this order from the top
each of which has a circular cylindrical shape. The large diameter
portion and the small diameter portion are (concentrically)
connected in the upward/downward direction with their axes being
aligned. A length in an axial direction (the upward/downward
direction) of the large diameter portion of the pin 535 is
comparable to the length of the cylinder 534. Specifically, the
length of the pin 535 is slightly greater than the distance between
the bottom surface (lower surface) of the base 533 coupled to the
cylinder 534 and the lower end of the cylinder 534. As shown in
FIG. 1, the small diameter portion of the pin 535 is fixed in the
through hole of the second yoke 62. In the present embodiment, part
including the small diameter portion of the pin 535 serves as the
second end 532 of the piston 53.
As shown in FIG. 4, the spring 536 is a coil spring. The spring 536
defines a relative position between the cylinder 534 and the pin
535. Specifically, the spring 536 is sandwiched between an inner
side surface of the cylinder 534 and an outer side surface of the
pin 535 to hold the pin 535 inside the cylinder 534.
The case 52 includes a holder 521, a sleeve 522, a cap 523, a first
holding spring 524, and a second holding spring 525. The case 52 is
formed in a substantially hollow circular cylindrical shape as a
whole.
The holder 521 of the case 52 is made of metal, for example,
aluminum or an aluminum alloy. The holder 521 has a substantially
hollow circular cylindrical shape with open upper and lower
surfaces and has an inner side surface which is a circumferential
surface with multiple steps. The holder 521 holds the squib 51 and
the piston 53.
The squib 51 is fitted into a space at an upper part of the holder
521 of the case 52. An inner surface of the upper part of the
holder 521 has a shape in substantially close contact with the
outer surface of the squib 51 (the outer side surface of the body
511, the outer surface of the flange part of the metal sleeve 512,
the outer side surface of the hollow circular cylindrical part of
the metal sleeve 512). The opening on the upper side of the holder
521 (the inner space thereof) is closed by the squib 51.
The base 533 of the piston 53 is fitted into a space of a lower
part of the holder 521 of the case 52. An inner surface of the
lower part of the holder 521 has a shape in substantially close
contact with the outer side surface of the first columnar section
of the base 533. An opening on a lower side of the holder 521 (the
inner space thereof) is closed by the piston 53 (the base 533
thereof).
By attaching the squib 51 and the piston 53 to the case 52, a
closed airtight space is formed between the lower surface of the
squib 51 (the metal sleeve 512 thereof), the upper surface of the
piston 53 (the base 533 thereof) and the inner surface of the case
52 (the holder 521 thereof). The gas generated by the squib 51 is
introduced into the airtight space through the broken portion of
the lower wall of the metal sleeve 512. That is, the airtight space
functions as the pressurized chamber 520 that receives the pressure
of the gas generated by the squib 51.
The sleeve 522 of the case 52 is made of metal, for example, steel.
The sleeve 522 is placed below the holder 521 to make its outer
side surface continuous to an outer side surface of the holder 521.
The sleeve 522 is formed in a substantially cylindrical shape
having open upper and lower surfaces. The sleeve 522 includes a
first cylindrical portion, a second cylindrical portion and a third
cylindrical portion which have a hollow circular cylindrical shape
and are arranged in this order from above. The first cylindrical
portion, the second cylindrical portion and the third cylindrical
portion are connected in the upward/downward direction with these
axes aligned (concentrically). The inner surface of the first
cylindrical portion is formed in a tapered shape with a smaller
diameter toward the lower side. The inner side surface of the
second cylindrical portion is formed in a hollow circular
cylindrical shape having a constant diameter. The inner diameter of
the second cylindrical portion is substantially equal to the outer
diameter of the first columnar section (the largest diameter
portion) of the base 533 of the piston 53. The inner side surface
of the third cylindrical portion is formed in a tapered shape with
a smaller diameter toward the lower side. The diameter of the inner
side surface of the third cylindrical portion is substantially
equal to the outer diameter of the first columnar section of the
base 533 (the largest diameter portion in the base 533) at its
upper end and becomes smaller toward the lower end. In other words,
the third cylindrical portion of the sleeve 522 has a shape not
allowing the base 533 of the piston 53 to pass therethrough.
There are two channels 50 interconnecting the inside and the
outside of the case 52 formed in the side wall of the sleeve 522 of
the case 52. As shown in FIG. 1, each channel 50 includes a first
end 501 connected to the accommodation 70 and a second end 502
connected to the inside space of the case 52. Each channel 50 has a
circular cylindrical shape having a constant diameter. One of the
two channels 50 (a left channel 50 in FIG. 1) is formed in part of
the side wall of the sleeve 522 of the case 52 which faces the
first fixed terminal 1. The channel 50 guides the gas generated by
the squib 51 to allow the gas to blow into the predetermined space
S1 between the first movable contact 31 and the first fixed contact
11 (a space including a track of movement of the first movable
contact 31, see FIG. 7). That is, the gas generated by the squib 51
is introduced into the predetermined space S1 between the fixed
contact (first fixed contact) 11 and the movable contact (first
movable contact) 31 while the movable contactor 3 is in the open
position. The other of the two channels 50 (a right channel 50 in
FIG. 1) is formed in part of the side wall of the sleeve 522 of the
case 52 which faces the second fixed terminal 2.
The channel 50 guides the gas generated by the squib 51 to allow
the gas to blow into the predetermined space S2 between the second
movable contact 32 and the second fixed contact 21 (a space
including a track of movement of the second movable contact 32).
Each of the two channels 50 extends obliquely downward from the
inside to the outside of the case 52.
In the present embodiment, each channel 50 is linear. However, the
shape of the channel 50 is not particularly limited, and may be
another shape such as a curved shape, for example. The diameter of
the channel 50 is not particularly limited. The direction in which
the channel 50 extends is not particularly limited, and may extend
laterally (in a horizontal direction), for example. Further, there
is no particular limitation on the position where the channel 50 is
formed, and the channel 50 may be formed, for example, in a front
portion or a back portion of the side wall of the sleeve 522 of the
case 52. However, it is preferable that each of the channels 50 is
formed in a shape, a diameter, an orientation, and a position to
allow the gas generated by the squib 51 to blow into the
predetermined space S1 or the predetermined space S2.
The cap 523 of the case 52 is made of metal, for example, steel.
The cap 523 is placed below the sleeve 522 to make its outer side
surface continuous to the outer side surface of the sleeve 522. The
cap 523 has a hollow circular cylindrical shape with both upper and
lower surfaces open. A projecting portion (flange) projecting
inward is formed at the lower surface of the cap 523. An inner
diameter of the projecting portion (flange) is approximately equal
to the outer diameter of the cylinder 534 of the piston 53. The
piston 53 is an operating pin which moves in one direction in
response to reception of the pressure of the gas generated by the
squib 51.
In the present embodiment, the outer diameters of the holder 521,
the sleeve 522, and the cap 523 are equal to each other.
The first holding spring 524 includes a clamping portion having a
hollow disk shape and a holding portion having a hollow
frustoconical shape protruding obliquely upward from an inner side
surface of the clamping portion. The clamping portion of the first
holding spring 524 is sandwiched between the holder 521 and the
sleeve 522 of the case 52. Thereby, the first holding spring 524 is
sandwiched between the holder 521 and the sleeve 522. The first
holding spring 524 seals a gap at a boundary between the holder 521
and the sleeve 522. The holding portion is in contact with the
holding groove 5330 of the base 533 of the piston 53 and applies an
upward force to the base 533 to hold the base 533 (prevent downward
movement of the base 533).
The second holding spring 525 includes a clamping portion having a
hollow disk shape and a holding portion having a hollow
frustoconical shape protruding obliquely downward from an inner
side surface of the clamping portion. The clamping portion of the
second holding spring 525 is sandwiched between the sleeve 522 and
the cap 523 of the case 52. Thereby, the second holding spring 524
is sandwiched between the sleeve 522 and the cap 523. The second
holding spring 525 seals a gap at a boundary between the sleeve 522
and the cap 523. A protruding tip of the holding portion is away
from the outer side surface of the cylinder 534 of the piston 53. A
diameter of the protruding tip of the holding portion is
approximately equal to the outer diameter of the second columnar
section of the base 533 of the piston 53.
As shown in FIG. 4, in a state where the squib 51 and the piston 53
is attached to the case 52, the pin electrode 514 of the squib 51
protrudes from the upper surface of the case 52. Further, the small
diameter portion of the pin 535 protrudes downward from the lower
surface of the case 52.
As shown in FIG. 1, the pyroactuator 5 is attached to the housing 7
so that the case 52 closes the through hole 731 of the cover member
73. In this state, the second end of the piston 53 (the lower end
of the pin 535) faces the center of the movable contactor 3 (the
center in the length direction and the width direction).
(1.2.3) Operation
Next, the operation of the circuit interrupter 100 having the
above-described configuration will be described with reference to
FIGS. 1, 6, 7.
As to the circuit interrupter 100, the first electrode 12 is
connected to the first end of the electric circuitry (e.g., the
circuitry constituting the power supply system 200) and the second
electrode 22 is connected to the second end of the electric
circuitry. Here, the first end of the electric circuitry is given a
higher potential than the second end.
In a normal state of the electric circuitry, the movable contactor
3 is held by the spring force of the pressure spring 41 and the
like so that the first movable contact 31 is connected to the first
fixed contact 11 and the second movable contact 32 is connected to
the second fixed contact 21 (see FIG. 1). In summary, in the normal
state of the electric circuitry, the movable contactor 3 is in the
closed position where the first movable contact 31 is in contact
with the first fixed contact 11 and the second movable contact 32
is in contact with the second fixed contact 21. At this time, a
current flows from the first electrode 12 to the second electrode
22 by passing through the first fixed contact 11, the first movable
contact 31, the movable contactor 3, the second movable contact 32,
and the second fixed contact 21 in this order.
At this time, the contact between the first movable contact 31 and
the first fixed contact 11 and the contact between the second
movable contact 32 and the second fixed contact 21 are maintained
by the spring force of the contact pressure spring 41, the
attraction force between the first yoke 61 and the second yoke 62,
and the like. Incidentally, even if an overcurrent or the like
flows in the circuit interrupter 100, contact between the contacts
is maintained due to the attraction force between the first yoke 61
and the second yoke 62 and the like as long as the magnitude of the
overcurrent is relatively small.
When the current flowing through becomes an abnormal current with
its value equal to or higher than a prescribed value (in an
abnormal state of the electric circuitry), the control circuitry
207 detects the abnormal current. Upon detecting the abnormal
current, the control circuitry 207 operates (activates) the circuit
interrupter 100 to break the electric circuitry.
Specifically, the control circuitry 207 allows a current to flow
between the pair of pin electrodes 514 to energize the heating
element 515. When energized, the heating element 515 generates heat
and increases the temperature of the combustion part 513. When the
temperature of the combustion part 513 exceeds the ignition
temperature of the explosive, the explosive is combusted to
generate a large amount of gas and the low strength portion of the
lower wall of the metal sleeve 512 is broken by the pressure of the
gas and the gas is discharged to the pressurized chamber 520
through the broken portion. Since the combustion part 513
explosively combusts to generate a large amount of gas, the
pressure in the pressurized chamber 520 rapidly increases in a
short time.
In an initial state, the piston 53 is in the first position (see
FIG. 1). The piston 53 receives the pressure in the pressurized
chamber 520 with the first end 531 (the upper surface of the base
533) and then is pressed downward to press the movable contactor 3
downward with the second end 532 (the pin 535). The piston 53
applies a force to part of the movable contactor 3 between the
first movable contact 31 and the second movable contact 32 to move
the movable contactor 3 downward. The piston 53 moves to the second
position (see FIG. 7) while pressing the movable contactor 3.
Specifically, in the piston 53, the bottom surface (upper surface)
of the base 533 receives the pressure in the pressurized chamber
520 and the base 533 starts to move downward together with the
cylinder 534 against the spring force of the first holding spring
524. An initial speed of the base 533 (the piston 53) at this time
becomes very large because of the large pressure in the pressurized
chamber 520. The pin 535 receives a downward force from the
cylinder 534 via the spring 536 and starts to move downward
slightly later from the start of downward movement of the cylinder
534. The pin 535, the second yoke 62, the first yoke 61 and the
movable contactor 3 is provided as an integral part. Due to
downward movement of the pin 535, the movable contactor 3 is
pressed downward and then moves downward. Here, after start of
downward movement of the base 533, an elastic force stored in the
spring 536 acts on the pin 535 and therefore a very large downward
force is applied on the pin 535 and thus the initial speed also
increases.
A force pressing the movable contactor 3 downward exceeds a force
supporting the movable contactor 3 upward (the spring force of the
contact pressure spring 41, the attraction force between the first
yoke 61 and the second yoke 62, and the like), the movable
contactor 3 moves downward while compressing the contact pressure
spring 41 through the first yoke 61. Thus, the first movable
contact 31 is separated from the first fixed contact 11 and the
second movable contact 32 is separated from the second fixed
contact 21 (see FIG. 6). As a result, the electric path between the
first fixed terminal 1 and the second fixed terminal 2 is
interrupted and the current flowing through the electric path
between the first fixed terminal 1 and the second fixed terminal 2
is interrupted.
The piston 53, the first yoke 61, the movable contactor 3, and the
second yoke 62 is integrally moved downward (hereinafter, for
convenience of explanation, a set of the piston 53, the first yoke
61, the movable contactor 3, and the second yoke 62 is referred to
as a movable body). A direction in which the piston 53 moves and a
direction in which the movable contactor 3 moves by the piston 53
are the same direction. Typically, the movable body moves to a
position where the contact pressure spring 41 is most compressed
(the second position) (see FIG. 7). In summary, the movable
contactor 3 moves to the open position where the first movable
contact 31 is separated from the first fixed contact 11 and the
second movable contact 32 is separated from the second fixed
contact 21. At this time, the base 533 of the piston 53 moves
inside the third cylindrical portion while pressing and expanding
(modifying) the inner surface of the third cylindrical portion of
the sleeve 522 of the case 52. Incidentally, kinetic energy of the
movable body is converted into elastic energy of the contact
pressure spring 41, thermal energy generated when the movable body
strikes the bottom surface of the inner hollow cylinder 71, and the
like.
The movable body receives an upward force from the compressed
contact pressure spring 41 at a position where the contact pressure
spring 41 is compressed. However, the upward movement of the
movable body is blocked by a frictional force between the base 533
and the third cylindrical portion of the sleeve 522 of the case 52.
As a result, the movable body stops at a position shown in FIG. 7
(the second position). In other words, the third cylindrical
portion functions as a detent mechanism that mechanically holds the
piston 53 after movement of the movable contactor 3 to prevent the
piston 53 from returning to its original position (the first
position).
Further, the downward movement of the piston 53 (movement from the
first position to the second position) extends the space in the
case 52 the pressure of which is increased by introduction of the
gas of the squib 51 (the pressurized chamber 520). As shown in FIG.
7, extension of the pressurized chamber 520 allows the second end
502 of each channel 50 to be connected to the pressurized chamber
520. As a result, the pressurized chamber 520 and the accommodation
70 are interconnected by the channel 50. Therefore, the gas
generated by the squib 51 is introduced into the accommodation 70
through the pressurized chamber 520 and the channel 50. In the
present embodiment, the gas introduced into the accommodation 70
goes to the predetermined space S1 between the first movable
contact 31 and the first fixed contact 11 or the predetermined
space S2 between the second movable contact 32 and the second fixed
contact 21 (see arrow W1 in FIG. 7).
Here, when the first movable contact 31 is pulled away from the
first fixed contact 11 while a current flows in the movable
contactor 3, there is a possibility that an arc is generated
between the first movable contact 31 and the first fixed contact 11
(see dotted line A1 in FIG. 8A). Similarly, when the second movable
contact 32 is pulled away from the second fixed contact 21 while a
current flows in the movable contactor 3, there is a possibility
that an arc is generated between the second movable contact 32 and
the second fixed contact 21.
In contrast, in the circuit interrupter 100 of the present
embodiment, the gas generated by the squib 51 of the pyroactuator 5
(electrically insulating gas) is introduced into the accommodation
70, thereby increasing the pressure of the accommodation 70. The
accommodation 70 forms a sealed space together with the pressurized
chamber 520. The accommodation 70 accommodates the fixed contact
(first fixed contact) 11 and the movable contact (first movable
contact) 31 therein, and includes the predetermined space S1. The
accommodation 70 is also a space where an arc occurs therein.
Increase in the pressure of the accommodation 70 causes the arc
generated between the contacts to be cooled. Therefore, the
electrically insulating properties of the plasma of the arc
discharge or the metal vapor is enhanced and the extinction of the
arc is promoted.
Further, in the circuit interrupter 100 of the present embodiment,
the gas introduced from the channel 50 into the accommodation 70
blows into the predetermined space S1 between the first movable
contact 31 and the first fixed contact 11, or the predetermined
space S2 between the second movable contact 32 and the second fixed
contact 21. Thus, the arc generated between the contacts is cooled
and the arc extinction is promoted.
More specifically, as to a process of movement of the movable
contactor 3 from the closed position to the open position, in the
early stage of movement from the closed position to the open
position, a positive column of the arc discharge is developed
between the fixed contact (first fixed contact) 11 and the movable
contactor 3 (see dotted line A1 in FIG. 8A). As the position is
changed from the closed position to the open position, the gas is
introduced into the accommodation 70. The gas strikes the positive
column and then the positive column is deformed by the pressure of
the gas, thereby stretching the arc (see dotted line A2 in FIG.
8B). Furthermore, the arc is stretched by the gas. In some cases
the arc is pressed against the wall surface of the inner hollow
cylinder 71 (see dotted line A3 in FIG. 8C). Thus, the arc is
stretched by the gas and then the arc is interrupted. That is, the
gas generated by the squib 51 is introduced into a gap between the
fixed contact (first fixed contact) 11 and the movable contactor 3.
Thereby, the arc extinction is promoted and the interruption
performance can be improved. Incidentally, the arc generated
between the second movable contact 32 and the second fixed contact
21 is blown by the gas and then stretched. Thus, the arc extinction
is promoted.
Thus, in the circuit interrupter 100 of the present embodiment, the
gas generated by the squib 51 is introduced into the predetermined
spaces S1, S2. Thereby, it is possible to quickly extinguish the
arc.
The inner wall (inner hollow cylinder 71) of the housing 7 may be
made of a resin material (arc extinction gas generating member)
which releases an arc extinction gas by being heated by a stretched
arc. Examples of the arc extinction gas may include CO.sub.2 gas,
N.sub.2 gas, and H.sub.2O gas. The arc extinction gas makes it
possible to quickly extinguish the arc.
(1.3) Variations
The circuit interrupter 100 of one variation of embodiment 1 will
be described with reference to FIGS. 9,10. Hereinafter, the circuit
interrupter 100 of embodiment 1 described above is also referred to
as the circuit interrupter 100 of the basic example of embodiment
1.
FIGS. 9, 10 show cross-sectional views of the circuit interrupter
100 of one variation before and after operation. Only for
convenience, the first yoke 61 and the second yoke 62 are not
depicted in FIGS. 9, 10. In FIGS. 9, 10, the illustration of the
case 52 is simplified. However, similarly to the circuit
interrupter 100 of embodiment 1, the case 52 may include, as the
detent mechanism, the second cylindrical portion (a portion having
a frustoconical inner surface whose diameter decreases toward the
lower side) and the third cylindrical portion (a portion having a
cylindrical inner surface having a smaller diameter than the base
533 of the piston 53). Further, in the circuit interrupter 100 of
one variation, the piston 53 is one molded article. Further, in the
circuit interrupter 100 of one variation, although the shapes of
the first fixed terminal 1 and the second fixed terminal 2 are
different from those of the circuit interrupter 100 of the basic
example of embodiment 1 but may be the same.
In the circuit interrupter 100 of one variation, the channel 50 has
a tapered cylindrical shape which is gradually smaller in diameter
toward the outside (the accommodation 70) of the case 52 than at
the inside of the case 52. That is, a diameter of the first end 501
of the channel 50 (an end close to the accommodation 70) is smaller
than a diameter of the second end 502. Thus, a flow rate of the gas
flowing from the second end 502 to the first end 501 is increased
in the channel 50. Thus, the flow rate of the gas in the
predetermined space S1, S2 is increased. Therefore, it is possible
to cool the arc generated between the contacts more effectively and
to further promote the arc extinction.
Further, in the circuit interrupter 100 of one variation, the
predetermined space S1 between the first fixed contact 11 and the
first movable contact 31 while the movable contactor 3 is in the
open position is located on an extension line of one channel 50
(the left one in FIGS. 9, 10). In other words, the extension line
of one channel 50 intersects a line segment interconnecting the
first movable contact 31 of the movable contactor 3 after movement
and the first fixed contact 11 (referred to as a "first line
segment"). In particular, the extension of one channel 50
intersects the first line segment in the vicinity of the first
fixed contact 11. Further, the predetermined space S2 between the
second fixed contact 21 and the second movable contact 32 while the
movable contactor 3 is in the open position is located on an
extension line of the other channel 50 (the right one in FIGS. 9,
10). In other words, the extension line of the other channel 50
intersects a line segment interconnecting the second movable
contact 32 of the movable contactor 3 after movement and the second
fixed contact 21 (referred to as a "second line segment"). In
particular, the extension of the other channel 50 intersects the
second line segment in the vicinity of the second fixed contact 21.
With this configuration, in the circuit interrupter 100 of one
variation, gases introduced into the accommodation 70 from the
individual channels 50 goes to the predetermined spaces S1, S2
which are spaces between the contacts, and thus blow the arcs
generated between the contacts directly (see arrow W2 in FIG. 10).
Therefore, it is possible to cool the arc more effectively and to
further promote the arc extinction. In addition, the arc can be
extended more effectively and further the arc extinction can be
promoted.
In the circuit interrupter 100 of the basic example and one
variation of embodiment 1, the channel 50 is not limited to a
columnar (cylindrical) shape formed in the side wall of the case
52. The channel 50 may be, for example, a cutout extending upward
from the lower end of the side wall of the case 52.
In the circuit interrupter 100 of the basic example and one
variation of embodiment 1, the pyroactuator 5 is not limited to
being configured to move the movable contactor 3 by use of the
piston 53. For example, the circuit interrupter 100 of embodiment 1
may be configured to allow the movable contactor 3 to receive the
pressure of the gas generated in the squib 51 directly (the movable
contactor 3 forms part of the outer wall of the pressurized chamber
520) and to allow the movable contactor 3 to be moved directly by
the pressure of the gas. In this case, the channel 50 may not be
provided in the case 52.
(2) Embodiment 2
The circuit interrupter 100 of embodiment 2 will be described with
reference to FIGS. 11, 12.
The circuit interrupter 100 of embodiment 2 is mainly different
from embodiment 1 in that the moving mechanism for moving the
movable contactor 3 from the closed position to the open position
includes a trip device 8. Configurations common to the circuit
interrupter 100 of embodiment 2 and embodiment 1 are denoted by the
same reference signs and explanations thereof are omitted
appropriately.
(2.1) Configuration
Similarly to embodiment 1, the circuit interrupter 100 of the
present embodiment includes the first fixed terminal 1, the second
fixed terminal 2, the movable contactor 3, the holding unit 4 (the
contact pressure spring 42 serving as an elastic part), the squib
51, the case 52, and the housing 7. However, in the circuit
interrupter 100 of the present embodiment, the moving mechanism
includes the trip device 8 instead of the pressurized chamber 520
and the piston 53. The trip device 8 moves the movable contactor 3
from the closed position to the open position in accordance with
the abnormal current flowing in the circuit including the movable
contact (first movable contact) 31 and the fixed contact (first
fixed contact) 11.
As shown in FIG. 11, the trip device 8 of the present embodiment
includes, an excitation coil 81, a mover 82, a stator 83, and a
hollow cylindrical body 84. The trip device 8 of the present
embodiment moves the movable contactor 3 to the open position by
use of an electromagnetic force generated by a magnetic flux
generated in the excitation coil 81 when the abnormal current flows
through the excitation coil 81.
The excitation coil 81 includes a first end connected to the first
fixed terminal 1. The excitation coil 81 includes a second end to
be connected to the first end of the electric circuitry (circuitry
constituting the power supply system 200) the second end of which
is to be connected to the second fixed terminal 2. That is, the
excitation coil 81 is connected in series with a series circuit of
the first fixed terminal 1, the movable contactor 3, and the second
fixed terminal 2 between the first end and the second end of the
electric circuitry. Therefore, a current flowing through the
movable contactor 3 also flows through the excitation coil 81. The
excitation coil 81 is excited by this current. As shown in FIG. 11,
the excitation coil 81 is wound around a lower portion of the
hollow cylindrical body 84 and the stator 83.
The hollow cylindrical body 84 is made of a non-magnetic metal
material. The hollow cylindrical body 84 includes a hollow
cylindrical part formed in a hollow cylindrical shape and a bottom
wall (lower wall) for closing one (lower) opening of the hollow
cylindrical part. More specifically, the hollow cylindrical body 84
includes the hollow cylindrical part having a hollow circular
cylindrical shape and the bottom wall having a circular shape, and
is formed into a bottomed hollow circular cylindrical shape with an
open upper surface as a whole. There is a through hole formed in a
center of the bottom wall of the housing 7. The hollow cylindrical
body 84 is fixed to the bottom wall of the housing 7 with its upper
end (the periphery of the opening) to cover the through hole of the
bottom wall of the housing 7.
The mover 82 is a moving iron core also formed in the shape of a
cylinder. The mover 82 is made of a magnetic material. The mover 82
is accommodated in the hollow cylindrical body 84. The mover 82 is
placed inside the hollow cylindrical body 84 to be movable in the
upward/downward direction. In the hollow cylindrical body 84, the
contact pressure spring 42 (the holding unit 4) is placed between
the bottom wall (the upper surface thereof) of the hollow
cylindrical body 84 and the mover 82 (the lower surface thereof).
There is a holding rib 841 on the upper surface of the bottom wall
of the hollow cylindrical body 84. The holding rib 841 is inserted
into a lower end of the contact pressure spring 42. The mover 82 is
pressed upward by the contact pressure spring 42. The mover 82 is
movable between a first position in which the mover 82 is pressed
upward by the contact pressure spring 42 and is in the upmost
position (see FIG. 11) and a second position in which the mover 82
compresses the contact pressure spring 42 and is in the lowermost
position (see FIG. 12). However, the mover 82 is always held in the
first position by a spring force of the contact pressure spring 42.
The mover 82 is coupled to the movable contactor 3 by a shaft 831
which penetrates through the through hole in the bottom wall of the
housing 7.
The shaft 831 is made of a non-magnetic metallic material and has a
round bar shape with a length in the upward/downward direction. An
upper end of the shaft 831 is coupled to a center of the movable
contactor 3. The shaft 831 passes through the through hole formed
in the bottom wall of the housing 7 and a lower end thereof is
coupled to the mover 82. Therefore, upward/downward movement of the
mover 82 is transferred to the movable contactor 3 via the shaft
831. The movable contactor 3 moves in the upward/downward direction
in synchronization with the movement of the mover 82.
As shown in FIG. 11, when the mover 82 is in the first position,
the first movable contact 31 and the second movable contact 32 of
the movable contactor 3 are in contact with the first fixed contact
11 and the second fixed contact 21, respectively. That is, when the
mover 82 is in the first position, the movable contactor 3 is in
the closed position. As shown in FIG. 12, when the mover 82 is in
the second position, the first movable contact 31 and the second
movable contact 32 of the movable contactor 3 are separated from
the first fixed contact 11 and the second fixed contact 21,
respectively. That is, when the mover 82 is in the second position,
the movable contactor 3 is in the open position (see FIG. 12).
The stator 83 is a fixed iron core formed in the shape of a
cylinder. The stator 83 is made of a magnetic material. The stator
83 is fixed below the bottom wall of the hollow cylindrical body
84.
In the trip device 8, all of the excitation coil 81, the mover 82
and the stator 83 have their central axes on the same straight line
along the upward/downward direction.
The trip device 8 moves the mover 82 from the first position (the
position shown in FIG. 11) to the second position (the position
shown in FIG. 12) by the magnetic flux generated in the excitation
coil 81 in response to the abnormal current which flows through the
movable contactor 3 and has a value equal to or larger than the
prescribed value. At this time, the movable contactor 3 is pulled
by the shaft 831 to move from the closed position to the open
position.
That is, the trip device 8 moves the mover 82 to the second
position by the magnetic flux generated in the excitation coil 81
in response to the abnormal current flowing through the movable
contactor 3, thereby forcibly separating the movable contact (first
movable contact) 31 from the fixed contact (first fixed contact)
11. In the present embodiment, at this time, the second movable
contact 32 is also separated from the second fixed contact 21.
Hereinafter, the operation in which the trip device 8 forcibly
separates the movable contact (first movable contact) 31 from the
fixed contact (first fixed contact) 11 is referred to as
"trip".
Here, the trip device 8 does not make trip just when the current
flows through the excitation coil 81. The trip device 8 makes trip
when an attraction force acting on the mover 82 from the stator 83
exceeds the spring force of the contact pressure spring 42. The
attraction force acting on the mover 82 from the stator 83 changes
according to the magnitude of the current flowing through the
excitation coil 81 (the load current). The trip device 8 is
configured so that the magnetic attraction force generated by the
excitation coil 81 exceeds the spring force of the contact pressure
spring 42 when the current flowing through the excitation coil 81
becomes the abnormal current with its value equal to or larger than
the prescribed value.
There is a magnet 9 placed between the stator 83 and the bottom
wall of the hollow cylindrical body 84. The magnet 9 is a permanent
magnet and includes on its opposite surfaces in the upward/downward
direction a first pole surface and a second pole surface which are
different in polarities. The first pole surface (upper surface) of
the magnet 9 is in contact with the bottom wall of the hollow
cylindrical body 84. The second pole surface (the lower surface) of
the magnet 9 is in contact with the stator 83. That is, the magnet
9 is sandwiched between the stator 83 and the bottom wall of the
hollow cylindrical body 84. For example, the first pole surface and
the second pole surface may be an N-pole surface and an S-pole face
and vice versa.
When the trip device 8 moves the mover 82 to the second position,
the magnet 9 holds the mover 82 in the second position by the
magnetic flux generated by the magnet 9. That is, the circuit
interrupter 100 of the present embodiment, after the trip device 8
moves the mover 82 to the second position, the mover 82 is held in
the second position by the magnetic attraction force generated by
the magnet 9. In other words, once the trip device 8 makes trip and
the mover 82 is moved to the second position, the mover 82 is held
(latched) in the second position by the magnet 9.
In the present embodiment, the magnet 9 is placed so that the
direction of the magnetic flux generated in the excitation coil 81
and the direction of the magnetic flux generated in the magnet 9
are the same in the mover 82 after the mover 82 is moved to the
second position by the trip device 8. That is, when the mover 82 is
in the second position, the magnetic flux generated in the
excitation coil 81 and the magnetic flux generated in the magnet 9
pass through the mover 82. Then, in the present embodiment, the
polarities (directions of the pole surfaces) of the magnet 9 are
set to generate the magnetic flux in the same direction as the
magnetic flux generated by the excitation coil 81 in the mover
82.
The circuit interrupter 100 of the present embodiment includes the
squib 51 and the case 52 in the pyroactuator 5 of the basic example
of embodiment 1, but does not include the piston 53. In the circuit
interrupter 100 of the present embodiment, the shape of the case 52
is different from that of the basic example of embodiment 1. The
squib 51 of the present embodiment is the same as the basic example
of embodiment 1 and explanation thereof is omitted.
The case 52 is made of metal, for example, aluminum or an aluminum
alloy. The case 52 is formed in a bottomed hollow circular
cylindrical shape with an open upper surface and a closed lower
surface.
The squib 51 is fitted into a space in an upper portion of the case
52. An upper opening of the case 52 (the inside space thereof) is
closed by the squib 51. The case 52 is fixed to the housing 7 to
close the through hole 731 of the cover member 73.
There are two channels 50 interconnecting the inside and the
outside of the case 52 formed in right and left side portions of
the lower surface of the case 52. Each channel 50 includes a first
end 501 connected to the accommodation 70 and a second end 502
connected to the inside space of the case 52. In the present
embodiment, there is no airtight space inside the case 52. In the
present embodiment, the gas generated in the squib 51 is directly
introduced into the accommodation 70 (through the inside space of
the case 52 and the channel 50).
Each channel 50 has a circular cylindrical shape having a constant
diameter. One of the two channels 50 (the left channel 50 in FIGS.
11, 12) guides the gas generated by the squib 51 to blow into the
predetermined space S1 between the first movable contact 31 and the
first fixed contact 11 (see FIG. 12). The other of the two channels
50 (the right channel 50 in FIGS. 11, 12) guides the gas generated
by the squib 51 to blow into the predetermined space S2 between the
second movable contact 32 and the second fixed contact 21 (see FIG.
12). Each of the two channels 50 extends obliquely downward from
the inside to the outside of the case 52.
(2.2) Operation
Next, the operation of the circuit interrupter 100 having the
above-described configuration will be described with reference to
FIGS. 11, 12.
In the circuit interrupter 100 of the present embodiment, the
second end of the excitation coil 81 is connected to the first end
of the electric circuitry (e.g., the circuitry constituting the
power supply system 200) and the second electrode 22 is connected
to the second end of the electric circuitry.
In the normal state of the electric circuitry, the spring force of
the contact pressure spring 42 is greater than the attraction force
acting on the mover 82 from the stator 83. Therefore, the movable
contactor 3 is held mainly by this spring force so that the first
movable contact 31 is connected to the first fixed contact 11 and
the second movable contact 32 is connected to the second fixed
contact 21 (see FIG. 11). That is, in the normal state of the
electric circuitry, the mover 82 is in the first position farthest
from the stator 83. Further, in the normal state of the electric
circuitry, the movable contactor 3 is in the closed position where
the first movable contact 31 is in contact with the first fixed
contact 11 and the second movable contact 32 is in contact with the
second fixed contact 21. At this time, a current flows from the
first end of the electric circuitry to the second end of the
electric circuitry by passing through the excitation coil 81, the
first fixed terminal 1, the movable contactor 3, and the second
fixed terminal 2 in this order.
On the other hand, when the current flowing through the electric
circuitry (the excitation coil 81) becomes the abnormal current
having its value greater than or equal to the prescribed value (in
the abnormal state of the electric circuitry), the attraction force
acting on the mover 82 from the stator 83 exceeds the spring force
of the contact pressure spring 42. Thus, the trip device 8 makes
trip and therefore the mover 82 is moved to the second position and
the movable contactor 3 is moved to the open position. As a result,
the circuit between the first fixed terminal 1 and the second fixed
terminal 2 is interrupted and the current flowing through the
circuit between the first fixed terminal 1 and the second fixed
terminal 2 is interrupted.
Further, when the current flowing through the electric circuitry
(the excitation coil 81) becomes the abnormal current with its
value greater than or equal to the prescribed value, the control
circuitry 207 detects the abnormal current by the current sensor
206, for example. Upon detecting the abnormal current, the control
circuitry 207 makes a current flow across the pair of pin
electrodes 54 of the squib 51 to energize the heating element 515.
Thus, the explosive of the combustion part 513 is combusted to
generate a large amount of gas and the low strength portion of the
lower wall of the metal sleeve 512 is broken by the pressure of the
gas and the gas is discharged to the inside space of the case 52
through the broken portion.
The gas generated by the squib 51 is introduced into the
accommodation 70 through the channel 50 of the case 52. The gas
introduced into the accommodation 70 goes to the predetermined
space S1 between the first movable contact 31 and the first fixed
contact 11 or the predetermined space S2 between the second movable
contact 32 and the second fixed contact 21 (see arrow W3 in FIG.
12).
Even in the circuit interrupter 100 of the present embodiment, the
gas generated by the squib 51 (electrically insulating gas) is
introduced into the accommodation 70, thereby increasing the
pressure of the accommodation 70. Accordingly, the arc generated
between the contacts is cooled. Therefore, the electrically
insulating properties of the plasma of the arc discharge or the
metal vapor is enhanced and the extinction of the arc is
promoted.
Further, the gas introduced from the channel 50 into the
accommodation 70 blows into the predetermined space S1 between the
first movable contact 31 and the first fixed contact 11, or the
predetermined space S2 between the second movable contact 32 and
the second fixed contact 21. Thus, the arc generated between the
contacts is cooled and the arc extinction is promoted.
Thus, even in the circuit interrupter 100 of the present
embodiment, the gas generated by the squib 51 is introduced into
the predetermined spaces S1, S2. Thereby, it is possible to quickly
extinguish the arc.
Incidentally, the timing at which the trip device 8 makes trip may
be prior or subsequent to the timing at which the squib 51 starts
to release the gas. The gas may be released from the squib 51
before the trip device 8 makes trip. The gas may be released from
the squib 51 after the trip device 8 makes trip. The release and
the trip may occur at the same time. It is preferable that the gas
is released from the squib 51 after the trip device 8 makes
trip.
(2.3) Variations
The circuit interrupter 100 of variation 1 of embodiment 2 will be
described with reference to FIGS. 13-15. FIG. 13 is a
cross-sectional view of primary part of the circuit interrupter 100
of variation 1 before operation. FIG. 14 is a side view in a
direction perpendicular to the sheet of FIG. 13 (from the right),
of the primary part of the circuit interrupter 100 of variation 1
before operation. FIG. 15 is a side view in the same direction as
FIG. 14, of the primary part of the circuit interrupter 100 of
variation 1 after operation. Hereinafter, the circuit interrupter
100 of embodiment 2 is also referred to as the circuit interrupter
100 of the basic example of embodiment 2.
As shown in FIGS. 13, 14, the circuit interrupter 100 of variation
1 includes only one set of the movable contact 31 and the fixed
contact 11 in the circuit interconnecting the first electrode 12
and the second electrode 22. Specifically, the first fixed terminal
1 is a plate-shaped member made of a metal material having
conductivity. The first fixed terminal 1 includes a first fixed
contact 11 at a first end (a left end in FIG. 14) and a second end
thereof (a right end in FIG. 14) functions as the first electrode
12. The second fixed terminal 2 is a plate-shaped member which is
made of a metal material having conductivity and is shorter than
the first fixed terminal 1. The second fixed terminal 2 is placed
to face the first fixed terminal 1 in the upward/downward
direction. The second fixed terminal 2 includes a first end (a
right end in FIG. 14) which functions as the second electrode 22.
The movable contactor 3 includes at a first end (a left end in FIG.
14) the movable contact 31 connected to the fixed contact 11. The
movable contactor 3 and the second fixed terminal 2 are not
interconnected by a contact set including a set of a movable
contact and a fixed contact, but are interconnected by a braided
wire 87 made by braiding copper wires.
The case 52 accommodating the squib 51 includes only one channel 50
at the center of its bottom wall. Then, the case 52 is placed to
allow the first end 501 of the channel 50 to face the predetermined
space S1 between the movable contact 31 and the fixed contact 11
(see FIG. 15). As a result, the gas is introduced in a direction
orthogonal to the predetermined space S1.
Although there is no illustration, similarly to the basic example
of embodiment 2, the circuit interrupter 100 of variation 1 also
includes the housing 7 accommodating therein the first fixed
contact 11, the movable contactor 3, and the upper end of the shaft
831. The squib 51 and the case 52, the braided wire 87, and part
(left part) of the second fixed terminal 2 are also placed inside
the housing 7 (the accommodation 70).
In the present variation, when the abnormal current flows in the
electric circuitry, the excitation coil 81 is excited to move the
mover 82 from the first position (the position shown in FIG. 14) to
the second position (the position shown in FIG. 15). Along with
this, the movable contactor 3 is moved from the open position (the
position shown in FIG. 14) to the open position (the position shown
in FIG. 15). Further, when the control circuitry 207 provides a
current to the squib 51, the gas is generated from the squib 51 and
the gas is blown into the predetermined space S1 between the
movable contact 31 and the fixed contact 11. As a result, the arc
generated between the contacts is cooled and therefore it is
possible to quickly extinguish the arc.
Incidentally, similarly to the basic example of embodiment 2, the
circuit interrupter 100 of the present variation may include the
magnet 9 for holding the mover 82 at the second position.
The circuit interrupter 100 of variation 2 of embodiment 2 will be
described with reference to FIGS. 16, 17.
The circuit interrupter 100 of the present variation is different
from the circuit interrupter 100 of the basic example of embodiment
2 in including permanent magnets 43 as the holding unit 4 instead
of the contact pressure contact spring 41. The other configurations
are same as those of the circuit interrupter 100 of the basic
example of embodiment 2 and therefore explanations thereof are
omitted.
In the circuit interrupter 100 of the present variation, as shown
in FIG. 17, the movable contactor 3 is formed to have a cross shape
in a top view and includes a body part 33 and a pair of protrusion
parts 34. The body part 33 has a length in the rightward/leftward
direction and includes the first movable contact 31 and the second
movable contact 32 at both ends in the length direction. The pair
of protrusion parts 34 protrude in the forward/backward direction
from side surfaces of the body part 33. Each of the protruding
parts 34 of the movable contactor 3 is provided with a permanent
magnet 43. As shown in FIG. 16, the center of the movable contactor
3 faces the bottom surface of the case 52. Further, a pair of
magnetic members (not shown), in particular iron pieces are
provided to the lower surface of the cover member 73 of the housing
7 to be in front and back of the case 52 (positions facing the
permanent magnets 43).
In variation 2, the iron pieces are attracted by the permanent
magnets 43. The first movable contact 31 and the second movable
contact 32 are connected to the first fixed contact 11 and the
second fixed contact 21 while the iron pieces and the permanent
magnets 43 are separated from each other (see FIG. 16).
Also in the present variation, when the trip device 8 makes trip,
the mover 82 is moved from the first position (the position shown
in FIG. 16) to the second position against the magnetic attraction
force between the iron pieces and the permanent magnets 43, and the
movable contactor 3 is moved from the closed position (the position
shown in FIG. 16) to the open position. Thus, the circuit between
the first fixed terminal 1 and the second fixed terminal 2 is
interrupted. At this time, the control circuitry 207 allows the
squib 51 to generate the gas and also allows the gas to be
introduced into the accommodation 70. As a result, the arc
generated between the contacts is cooled and therefore it is
possible to quickly extinguish the arc.
In the present variation, the magnetic member may be provided to
the movable contactor 3 and the permanent magnet 43 may be provided
to the cover member 73 of the housing 7. Further, a spacer may be
provided between the permanent magnet 43 and the magnetic member.
The movable contactor 3 may be maintained in the closed state while
the permanent magnet 43 is in direct contact with the magnetic
member. Further, the holding unit 4 may include both the contact
pressure spring 41 and the permanent magnet 43.
The circuit interrupter 100 of variation 3 of embodiment 2 will be
described with reference to FIG. 18.
The circuit interrupter 100 of the present variation is mainly
different from the circuit interrupter 100 of the basic example of
embodiment 2 in including as the trip device 8, a bimetallic plate
88 instead of the excitation coil 81, the mover 82, the stator 83,
and the hollow cylindrical body 84. The other configurations are
same as those of the circuit interrupter 100 of the basic example
of embodiment 2 and therefore explanations thereof are omitted.
In the circuit interrupter 100 of the present variation, as shown
in FIG. 18, the movable contactor 3 is held in the closed position
by the contact pressure spring 41 similarly to the basic example of
embodiment 1. Further, the bimetallic plates 88 are attached to the
lower surfaces of the first fixed terminal 1 and the second fixed
terminal 2 with metal plates 89 in-between. The bimetallic plate 88
has its lower surface in contact with the upper surface of the
movable contactor 3.
In the present variation, when the abnormal current flows in the
movable contactor 3, the bimetallic plate 88 is curved downward
(see the dotted line in FIG. 18). Thus, the movable contactor 3 is
moved from the closed position to the open position.
That is, in the circuit interrupter 100 of the present variation,
when the abnormal current flows in the circuit including the
movable contact (first movable contact) 31 and the fixed contact
(first fixed contact) 11, the bimetallic plate 88 is curved and
thereby the movable contactor 3 is moved to the open position.
Thus, it is possible to interrupt the circuit between the first
fixed terminal 1 and the second fixed terminal 2.
The present variation may be provided with a holding mechanism for
holding the movable contactor 3 in the open position after the
movable contactor 3 is moved to the open position by the bimetallic
plate 88. For example, the holding mechanism may be a combination
of a permanent magnet and a magnetic member provided to the movable
contactor 3 and the inside wall of the housing 7. Further, the trip
device 8 may include the bimetallic plate 88 in addition to the
excitation coil 81, the mover 82, the stator 83 and the hollow
cylindrical body 84.
The circuit interrupters 100 of the basic example and variations
1-3 of embodiment 2 may also include the yokes 61, 62 similarly to
embodiment 1.
(3) Other Variations
The application of the circuit interrupter 100 is not limited to a
fuse for the vehicle 300. The circuit interrupter 100 may be used
for interrupting any electric circuitry through which a large
current, such as, for example, a short circuit current may flow.
Further, the circuit interrupter 100 may be a relay
(electromagnetic relay) including an electromagnet device.
A guide for defining the moving direction of the movable contactor
3 may be formed in the accommodation 70 of the housing 7. The guide
may be formed on the inner wall of the accommodation 70 to be long
in the upward/downward direction to be in contact with the side
surface of the movable contactor 3 along the moving direction of
the movable contactor 3. Thus, when the movable contactor 3 is
moved by the pyroactuator 5, the movable contactor 3 is less likely
to tilt. The guide may be a rod extending upward from the bottom
surface of the accommodation 70 and penetrating the movable
contactor 3.
The configurations of the basic examples and individual variations
of embodiments 1, 2 can be appropriately combined.
Referring to FIGS. 19-21, the circuit interrupter 100 according to
one concrete example (concrete example 1) of one variation obtained
by combining embodiments 1, 2 will be described. The circuit
interrupter 100 of the present concrete example functions as a
so-called normally-on ("b" contact) device. The circuit interrupter
100 includes the excitation coil 81, the squib 51, and the moving
mechanism.
As shown in FIG. 19, the fixed contact (first fixed contact) 11 of
the fixed terminal 1 (first fixed terminal) 1, the second fixed
contact 21 of the second fixed terminal 2, and the movable
contactor 3 including the movable contact (first movable contact)
31 and the second movable contact 32 are accommodated inside the
housing 7. The squib 51 is placed to face the upper surface of the
movable contactor 3. The housing 7 includes the through hole at its
bottom wall and the hollow cylindrical body 84 is fixed to cover
the through holes in the bottom wall. Further, the shaft 831 having
its upper end coupled to the movable contactor 3 is placed so that
the lower end thereof passes through the through hole in the bottom
wall of the housing 7 and is exposed inside the hollow cylindrical
body 84. The mover 82 and the contact pressure spring 42 are placed
inside the hollow cylindrical body 84. The mover 82 is coupled to
the lower end of the shaft 831. The stator 83 is fixed below the
bottom wall of the hollow cylindrical body 84. The excitation coil
81 is placed to surround the peripheries of the mover 82 and the
stator 83.
The movable contactor 3 is held by the spring force from the
contact pressure spring 42 and the like in the closed position in
which the movable contact (first movable contact) 31 is in contact
with the fixed contact (first fixed contact) 11 (see FIG. 19).
The excitation coil 81 and energization thereof are controlled by
the control circuitry 200. When the excitation coil 81 is
energized, the magnetic flux generated by the excitation coil 81
moves the mover 82 downward. When the mover 82 moves downward, the
shaft 831 and the movable contactor 3 also move downward together
with the mover 82. Thereby, the movable contactor 3 is moved from
the closed position (see FIG. 19) to the first open position (see
FIG. 20). On the other hand, when the energization of the
excitation coil 81 is stopped, the mover 82 is moved upward by the
spring force of the contact pressure spring 42 and the like. The
movable contactor 3 is moved to the closed position (see FIG.
19).
The moving mechanism includes a space interconnecting the squib 51
and the movable contactor 3 (a space between the squib 51 and the
movable contactor 3). That is, the circuit interrupter 100 of the
present concrete example allows the movable contactor 3 to receive
the pressure of the gas generated in the squib 51 directly (the
movable contactor 3 forms part of the outer wall of the pressurized
chamber 520) and allows the movable contactor 3 to be moved
directly by the pressure of the gas from the squib 51. The moving
mechanism moves the movable contactor 3 from the closed position
(see FIG. 19) or the first open position (see FIG. 20) to a second
open position in which the movable contact (first movable contact)
31 is separated from the fixed contact (first fixed contact) 11
(see FIG. 21). The second open position here is a position of the
movable contactor 3 in which the movable contact (first movable
contact) 31 is farther away from the fixed contact (first fixed
contact) 11 than in the case where the movable contactor 3 is in
the first open position. That is, in the present concrete example,
a distance between the closed position and the second open position
is longer than a distance between the closed position and the first
open position. When the movable contactor 3 moves downward to the
second open position, the mover 82 also moves downward. The mover
82 is held (latched) in the position shown in FIG. 21 by the
magnetic flux generated by the magnet 9.
Referring to FIGS. 22, 23, the circuit interrupter 100 according to
another concrete example (concrete example 2) of one variation
obtained by combining embodiments 1, 2 will be described. The
circuit interrupter 100 of the present concrete example functions
as a so-called normally-off ("a" contact) device. Similarly to the
circuit interrupter 100 of concrete example 1, the circuit
interrupter 100 includes the excitation coil 81, the squib 51, and
the moving mechanism. Hereinafter, a description will be given
centering on different points from concrete example 1 described
above.
In the circuit interrupter 100 shown in FIG. 22, the stator 83 is
fixed to the bottom wall of the housing 7 inside the hollow
cylindrical body 84. The stator 83 includes at its center a through
hole extending in the upward/downward direction. The lower end of
the shaft 831 extends downward while passing through the through
hole of the bottom wall of the housing 7 and the through hole of
the stator 83, and is fixed to the mover 82. A return spring 85 is
placed between the mover 82 and the stator 83. The excitation coil
81 is placed to surround the peripheries of the mover 82 and the
stator 83.
The movable contactor 3 is held by the spring force received by the
mover 82 from the return spring 85 and the like in the first open
position where the movable contact (first movable contact) 31 is
separated from the fixed contact (first fixed contact) 11 (see FIG.
22).
When the excitation coil 81 is energized, the magnetic flux
generated by the excitation coil 81 moves the mover 82 upward. When
the mover 82 moves upward, the shaft 831 and the movable contactor
3 also move upward together with the mover 82. Thereby, the movable
contactor 3 is moved from the first open position (see FIG. 22) to
the closed position (see FIG. 23). On the other hand, when the
energization of the excitation coil 81 is stopped, the mover 82 is
moved downward by the spring force of the return spring 85 and the
like. The movable contactor 3 is moved to the first open position
(see FIG. 22). That is, the circuit interrupter 100 of the present
concrete example functions as a so-called "a" contact type contact
device.
The moving mechanism is defined by a space interconnecting the
squib 51 and the movable contactor 3 (a space between the squib 51
and the movable contactor 3). That is, the movable contactor 3
directly receives the pressure of the gas from the squib 51 and
then is moved. The moving mechanism is configured to move the
movable contactor 3 to the second open position where the movable
contact (first movable contact) 31 is separated from the fixed
contact (first fixed contact) 11 (see FIG. 22). The second open
position here is the same as the first open position. That is, in
the present concrete example, the distance between the closed
position and the second open position is equal to the distance
between the closed position and the first open position. When the
movable contactor 3 moves downward to the second open position, the
mover 82 also moves downward.
Referring to FIGS. 24, 25, the circuit interrupter 100 according to
another concrete example (concrete example 3) of one variation
obtained by combining embodiments 1, 2 will be described. The
circuit interrupter 100 of the present concrete example includes a
structure of the circuit interrupter 100 of the basic example of
embodiment 2 (see FIG. 11), but the pyroactuator 5 thereof is
replaced with the pyroactuator 5 (the pyroactuator 5 including the
piston 53; see FIG. 9) of one variation of embodiment 1.
In the circuit interrupter 100 of the present concrete example,
when the gas is generated in the squib 51, the movable contactor 3
is pressed with the piston 53 which is moved by the pressure in the
pressurized chamber 520. Thereby, the movable contactor 3 is moved
to the open position. Further, in the circuit interrupter 100 of
the present concrete example, the movable contactor 3 can be moved
to the open position by also the electromagnetic force generated by
the magnetic flux caused by the excitation coil 81 when the
abnormal current flows in the excitation coil 81 of the trip device
8. FIG. 24 is a view of the circuit interrupter 100 of the present
concrete example and shows a state where both the squib 51 and the
trip device 8 do not operate. FIG. 25 is a view of the circuit
interrupter 100 of the present concrete example and shows a state
in which the piston 53 is pressed by the pressure of the gas from
the squib 51 and the movable contactor 3 is pressed by the piston
53 to move to the open position.
Referring to FIGS. 26-28, the circuit interrupter 100 according to
another concrete example (concrete example 4) of one variation
obtained by combining embodiments 1, 2 will be described. The
circuit interrupter 100 of the present concrete example includes a
structure of the circuit interrupter 100 of concrete example 1 (see
FIG. 19), but the pyroactuator 5 thereof is replaced with the
pyroactuator 5 (see FIG. 9) of one variation of embodiment 1.
In the circuit interrupter 100 of the present concrete example, the
movable contactor 3 moves between the closed position (see FIG. 26)
and the first open position (see FIG. 27) in response to switching
on and off of the energization of the excitation coil 81. That is,
while the excitation coil 81 is not energized, the movable
contactor 3 is held by the spring force from the contact pressure
spring 42 and the like in the closed position where the movable
contact (first movable contact) 31 is in contact with the fixed
contact (first fixed contact) 11. Further, when the excitation coil
81 is energized, the movable contactor 3 is held by the
electromagnetic force due to the magnetic flux generated in the
excitation coil 81 in the first open position where the movable
contact (first movable contact) 31 is separated from the fixed
contact (first fixed contact) 11. Further, when the pyroactuator 5
is activated and the squib 51 generates the gas, the piston 53 is
pressed downward by the pressure in the pressurized chamber 520 and
the movable contactor 3 is pressed by the piston 53 to be moved to
the second open position (see FIG. 28).
Referring to FIGS. 29-31, the circuit interrupter 100 according to
another concrete example (concrete example 5) of one variation
obtained by combining embodiments 1, 2 will be described. The
circuit interrupter 100 of the present concrete example includes a
structure of the circuit interrupter 100 of concrete example 2 (see
FIG. 22), but the pyroactuator 5 thereof is replaced with the
pyroactuator 5 (see FIG. 9) of one variation of embodiment 1.
In the circuit interrupter 100 of the present concrete example, the
movable contactor 3 moves between the closed position (see FIG. 30)
and the first open position (see FIG. 29) in response to switching
on and off of the energization of the excitation coil 81. That is,
while the excitation coil 81 is not energized, the movable
contactor 3 is held by the spring force from the return spring 85
and the like in the first open position where the movable contact
(first movable contact) 31 is separated from the fixed contact
(first fixed contact) 11. When the excitation coil 81 is energized,
the movable contactor 3 is held by the electromagnetic force due to
the magnetic flux generated in the excitation coil 81 in the closed
position where the movable contact (first movable contact) 31 is in
contact with the fixed contact (first fixed contact) 11. Further,
when the pyroactuator 5 is activated and the squib 51 generates the
gas, the piston 53 is pressed downward by the pressure in the
pressurized chamber 520 and the movable contactor 3 is pressed by
the piston 53 to be moved to the second open position (see FIG.
31). Here, the second open position is the same as the first open
position.
In the circuit interrupters 100 of concrete examples 1-5, the gas
generated by the squib 51 is introduced into the accommodation 70
of the housing 7, thereby promoting the arc extinction.
Further, in concrete examples 1, 2, 4, 5, while the pyroactuator 5
is not activated, the circuit interrupter 100 can be used as an
electromagnetic relay including a contact device.
The relationship among the closed position, the first open
position, and the second open position is not limited to the
positional relationship shown in each of the above-described
concrete examples. That is, the distance between the closed
position and the first open position may be longer than, shorter
than, or equal to the distance between the closed position and the
second open position. The distance between the closed position and
the second open position is preferably longer than the distance
between the closed position and the first open position.
In addition, the circuit interrupters 100 of concrete examples 3-5
may include the pyroactuator 5 of the basic example of embodiment
1.
In each concrete example, the case 52 may include, as the detent
mechanism, the second cylindrical portion (a portion having a
frustoconical inner surface whose diameter decreases toward the
lower side) and the third cylindrical portion (a portion having a
cylindrical inner surface having a smaller diameter than the base
533 of the piston 53).
Further, in each concrete example described above, the circuit
interrupter 100 may include a holder and a contact pressure spring.
The holder has a rectangular box shape with open left and right
surfaces to allow the movable contactor 3 to pass therethrough to
penetrate in the rightward/leftward direction. The upper end of the
shaft 831 is coupled to a lower wall of the holder. The contact
pressure spring is placed inside the holder to be positioned
between an upper surface of the lower wall of the holder and the
lower surface of the movable contactor 3, thereby biasing the
movable contactor 3 upward. With this configuration, it is possible
to ensure a contact pressure between the movable contact (first
movable contact) 31 and the fixed contact (first fixed contact) 11
and a contact pressure between the second movable contact 32 and
the second fixed contact 21 while the movable contactor 3 is in the
closed position.
(4) Aspects
As apparent from the aforementioned embodiments and variations, a
circuit interrupter (100) of a first aspect includes a fixed
terminal (1), a movable contactor (3), a moving mechanism, a squib
(51), and accommodation (70). The fixed terminal (1) includes a
fixed contact (11). The movable contactor (3) includes a movable
contact (31) connected to the fixed contact (11). The moving
mechanism is configured to move the movable contactor (3) from a
closed position to an open position. The closed position is a
position of the movable contactor (3) where the movable contact
(31) is connected to the fixed contact (11). The open position is a
position of the movable contactor (3) where the movable contact
(31) is separated from the fixed contact (11). The squib (51) is
configured to generate gas by combustion. The accommodation (70) is
for accommodating the fixed contact (11) and the movable contactor
(3). In the circuit interrupter (100), the gas is introduced into
the accommodation (70).
According to the first aspect, the gas generated by the squib (51)
is introduced into the accommodation (70) accommodating the fixed
contact (11) and the movable contactor (3). Therefore, even when
the arc is developed between the contacts, it is possible to
quickly extinguish the arc by the gas.
In a circuit interrupter (100) of a second aspect referring to the
first aspect, the gas is introduced into a predetermined space (S1)
between the fixed contact (11) and the movable contact (31) while
the movable contactor (3) is in the open position.
According to the second aspect, the gas generated by the squib (51)
is introduced into the predetermined space (S1) between the fixed
contact (11) and the movable contact (31) of the movable contactor
(3) in the open position. Therefore, even when the arc is developed
between the contacts, it is possible to quickly extinguish the arc
by the gas.
A circuit interrupter (100) of a third aspect referring to the
second aspect includes a channel (50) for guiding the gas to allow
the gas to blow into the predetermined space (S1).
According to the third aspect, the gas blows into the arc via the
channel (50). It is possible to promote the arc extinction.
In a circuit interrupter (100) of a fourth aspect referring to the
second or third aspect, the gas is introduced in a direction
perpendicular to the predetermined space (S1).
According to the fourth aspect, it is possible to deform or stretch
the arc developed in the predetermined space (S1) efficiently.
Thus, it is possible to promote the arc extinction and to improve
the interruption performance.
In a circuit interrupter (100) of a fifth aspect referring to any
one of the first to fourth aspects, the moving mechanism includes a
pressurized chamber (520) and a piston (53). The pressurized
chamber (520) is for receiving pressure of the gas. The piston (53)
is for receiving pressure inside the pressurized chamber (520) and
moving the movable contactor (3) in the closed position by applying
a force to the movable contactor (3) in a direction toward the open
position. In the circuit interrupter (100), part of the gas is
introduced into the predetermined space (S1) from the pressurized
chamber (520).
According to the fifth aspect, it is possible to move the movable
contactor (3) with the pressure of the gas (energy) and also
possible to quickly extinguish the arc generated between the
contacts by introduction of the gas into the predetermined space
(S1).
In a circuit interrupter (100) of a sixth aspect referring to any
one of the first to fourth aspects, the moving mechanism includes a
trip device (8). The trip device (8) is for moving the movable
contactor (3) from the closed position to the open position in
response to an abnormal current flowing through a circuit including
the movable contact (31) and the fixed contact (11).
According to the sixth aspect, as to the device using the trip
device (8) to interrupt the circuit (e.g., a relay), it is possible
to quickly extinguish the arc developed between the contacts.
In a circuit interrupter (100) of a seventh aspect referring to the
sixth aspect, the trip device (8) includes an excitation coil (81)
constituting part of the circuit. The trip device (8) is configured
to move the movable contactor (3) to the open position by an
electromagnetic force developed by a magnetic flux caused by the
excitation coil (81) in response to a flow of the abnormal current
through the circuit.
According to the seventh aspect, as to the device using the
electromagnetic force generated by the magnetic flux generated in
the excitation coil (81), it is possible to quickly extinguish the
arc developed between the contacts.
In a circuit interrupter (100) of an eighth aspect referring to the
sixth or seventh aspect, the trip device (8) includes a bimetallic
plate (88) which curves in response to a flow of the abnormal
current through the circuit. The trip device (8) is configured to
move the movable contactor (3) to the open position when the
bimetallic plate (88) curves in response to a flow of the abnormal
current through the circuit.
According to the eighth aspect, as to the device making the
bimetallic plate (88) curve to interrupt the circuit, it is
possible to quickly extinguish the arc developed between the
contacts.
A circuit interrupter (100) of a ninth aspect referring to any one
of the first to eighth aspects includes an elastic part (contact
pressure springs 41, 42) for providing an elastic force in a
direction toward the closed position, to the movable contactor
(3).
According to the ninth aspect, it is possible to hold the movable
contactor (3) in the closed position.
A circuit interrupter (100) of a tenth aspect referring to any one
of the first to ninth aspects includes a permanent magnet (43) for
holding the movable contactor (3) in the closed position.
According to the tenth aspect, it is possible to hold the movable
contactor (3) in the closed position.
A circuit interrupter (100) of an eleventh aspect referring to any
one of the first to tenth aspects includes a space which includes
the accommodation (70) and in which the gas is sealed.
According to the eleventh aspect, the gas is introduced into the
space in which the gas is sealed and thus the pressure in this
space is increased. Accordingly, it is possible to quickly
extinguish the arc developed between the contacts.
A circuit interrupter (100) of a twelfth aspect includes a fixed
terminal (1), a movable contactor (3), an excitation coil (81), and
a moving mechanism. The fixed terminal (1) includes a fixed contact
(11). The movable contactor (3) includes a movable contact (31)
connected to the fixed contact (11). The squib (51) is configured
to generate gas by combustion. The excitation coil (81) is
configured to move the movable contactor (3) from a closed position
where the movable contact (31) is connected to the fixed contact
(11) to a first open position where the movable contact (31) is
separated from the fixed contact (11). The moving mechanism is
configured to move the movable contactor (3) to a second open
position where the movable contact (31) is separated from the fixed
contact (11).
Configurations according to the second to eleventh aspects are
optional configurations for the circuit interrupter (100) and can
be omitted appropriately.
REFERENCE SIGNS LIST
100 Circuit Interrupter 1 First Fixed Terminal (Fixed Terminal) 11
First Fixed Contact (Fixed Contact) 3 Movable Contactor 31 First
Movable Contact (Movable Contact) 41 Contact Pressure Spring
(Elastic Part) 42 Contact Pressure Spring (Elastic Part) 43
Permanent Magnet 50 Channel 51 Squib 520 Pressurized Chamber 53
Piston 70 Accommodation 8 Trip Device 81 Excitation Coil 88
Bimetallic Plate S1 Predetermined Space
* * * * *